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For the transition period from to

Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act. Yes ☒ No ☐

Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act. Yes ☐ No ☒

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes ☒ No ☐

Indicate by check mark whether the Registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the Registrant was required to submit such files). Yes ☒ No ☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act. (Check one)

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Indicate by check mark whether the registrant has filed a report on and attestation to its management’s assessment of the effectiveness of its internal control over financial reporting under Section 404(b) of the Sarbanes-Oxley Act (15 U.S.C. 7262(b)) by the registered public accounting firm that prepared or issued its audit report. Yes ☒ No ☐

If securities are registered pursuant to Section 12(b) of the Act, indicate by check mark whether the financial statements of the registrant included in the filing reflect the correction of an error to previously issued financial statements. ☐

Indicate by check mark whether any of those error corrections are restatements that required a recovery analysis of incentive-based compensation received by any of the registrant’s executive officers during the relevant recovery period pursuant to §240.10D-1(b) ☐

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act). Yes ☐ No ☒

The aggregate market value of the shares of common stock held by non-affiliates of the registrant (treating all executive officers and directors of the registrant, for this purpose, as affiliates of the registrant) was $10,679 million as of September 30, 2025, the last business day of the registrant’s most recently completed second fiscal quarter, based on the reported closing price of the shares of common stock as reported on the New York Stock Exchange on September 30, 2025.

As of May 14, 2026, the registrant had 76,595,708 shares of common stock outstanding. The shares of common stock trade on the New York Stock Exchange under the ticker symbol “WMS.” In addition, as of May 14, 2026, 221,893 shares of unvested restricted common stock were outstanding and a total of 76,817,601 shares of common stock were outstanding, inclusive of outstanding shares of unvested restricted common stock.

Part III of this report incorporates by reference specific portions of the Registrant’s Notice of Annual Meeting and Proxy Statement relating to the Annual Meeting of Stockholders to be held on July 16, 2026, which statement will be filed no later than 120 days after the end of the fiscal year covered by this report.

This Annual Report on Form 10-K includes forward-looking statements. Some of the forward-looking statements can be identified by the use of terms such as “believes,” “expects,” “may,” “will,” “should,” “could,” “seeks,” “intends,” “plans,” “estimates,” “anticipates” or other comparable terms. These forward-looking statements include all matters that are not related to present facts or current conditions or that are not historical facts. They appear in a number of places throughout this Annual Report on Form 10-K and include statements regarding our goals, intentions, beliefs or current expectations concerning, among other things, our consolidated results of operations, financial condition, liquidity, prospects, growth strategies, and the industries in which we operate and include, without limitation, statements relating to our future performance.

Forward-looking statements are subject to known and unknown risks and uncertainties, many of which are beyond our control. We caution that forward-looking statements are not guarantees of future performance and that our actual consolidated results of operations, financial condition, liquidity, and industry development may differ materially from those made in or suggested by the forward-looking statements contained in this Annual Report on Form 10-K. In addition, even if our actual consolidated results of operations, financial condition, liquidity, and industry development are consistent with the forward-looking statements contained in this Annual Report on Form 10-K, those results or developments may not be indicative of results or developments in subsequent periods. A number of important factors could cause actual results to differ materially from those contained in or implied by the forward-looking statements, including those reflected in forward-looking statements relating to our operations and business, the risks and uncertainties discussed in this Annual Report on Form 10-K (including under the heading “Item 1A. Risk Factors”) and those described from time to time in our other filings with the SEC. Factors that could cause actual results to differ from those reflected in forward-looking statements relating to our operations and business include, among other things:

•fluctuations in the price and availability of resins and other raw materials, new tariff and international trade policies, and our ability to pass any increased costs of raw materials and tariffs on to our customers in a timely manner;

•disruption or volatility in general business, political and economic conditions in the markets in which we operate;

•cyclicality and seasonality of the non-residential and residential construction markets and infrastructure spending;

•the risks of increasing competition in our existing and future markets;

•uncertainties surrounding the integration and realization of anticipated benefits of acquisitions or doing so within the intended timeframe, including our ability to successfully integrate National Diversified Sales (“NDS”) into our business;

•risks that the acquisition of NDS may involve unexpected costs, liabilities, risks that the cost savings and synergies from the acquisition of NDS may not be fully realized;

•the effect of any claims, litigation, investigations or proceedings, including those described under “Item 3. Legal Proceedings” of this Annual Report;

•the effect of weather or seasonality;

•the loss of any of our significant customers;

•the risks of doing business internationally;

•the risks of conducting a portion of our operations through joint ventures;

•our ability to expand into new geographic or product markets;

•the risk associated with manufacturing processes;

•the effects of global climate change and any related regulatory responses;

•our ability to protect against cybersecurity incidents and disruptions or failures of our IT systems;

•our ability to assess and monitor the effects of artificial intelligence, machine learning, robotics and blockchain or other new approaches to data mining on our business and operations;

•our ability to manage our supply purchasing and customer credit policies;

•our ability to control labor costs and to attract, train and retain highly qualified employees and key personnel;

•our ability to protect our intellectual property rights;

•changes in laws and regulations, including environmental laws and regulations;

•our ability to appropriately address any environmental, social or governance concerns that may arise from our activities;

•the risks associated with our current levels of indebtedness, including borrowings under our existing credit agreement and outstanding indebtedness under our existing senior notes; and

•other risks and uncertainties, including those listed under “Item 1A. Risk Factors.”

Please read this Annual Report on Form 10-K completely and with the understanding that actual future results may be materially different from expectations. All forward-looking statements made in this Annual Report on Form 10-K are qualified by these cautionary statements. All forward-looking statements are made only as of the date of this Annual Report on Form 10-K, and we do not undertake any obligation, other than as may be required by law, to update or revise any forward-looking statements to reflect future events or developments. Comparisons of results for current and any prior periods are not intended to express any future trends, or indications of future performance, unless expressed as such, and should only be viewed as historical data.

Unless the context otherwise indicates or requires, as used in this Annual Report on Form 10-K, the terms “we,” “our,” “us,” “ADS” and the “Company” refer to Advanced Drainage Systems, Inc. and its directly- and indirectly-owned subsidiaries as a combined entity, except where it is clear that the terms mean only Advanced Drainage Systems, Inc. exclusive of its subsidiaries. The term “Infiltrator” refers to Infiltrator Water Technologies, LLC, our wholly-owned subsidiary.

ADS is the leading manufacturer of innovative water management solutions in the stormwater and onsite wastewater industries, providing superior drainage solutions to manage the world’s most precious resource: water. Our innovative products are used across a broad range of end markets and applications, including residential, non-residential, infrastructure and agriculture applications. We have established a leading position in many of these end markets by leveraging our national sales and distribution platform, market share model, industry-acclaimed engineering support, overall product breadth and scale plus manufacturing excellence. Our best-in-class product portfolio, go-to-market strategy and material conversion strategy helped drive consistent above market growth.

On February 2, 2026, we completed the acquisition of National Diversified Sales (“NDS”). NDS is a leading designer and manufacturer of residential stormwater and drainage solutions focused on managing surface and subsurface water around homes. NDS develops durable, easy‑to‑install products that help homeowners and contractors control runoff, prevent water damage, and protect landscapes and foundations. This combination brings together complementary water management solutions to expand our offerings. By adding NDS’ expertise in residential water management solutions, access boxes and irrigation to our product portfolio, we further enhance our capabilities as a comprehensive provider of full-scale water management solutions.

We believe the ADS brand has long been associated with quality products and market-leading performance. Our trademarked green stripe, which is prominently displayed on many of our products, serves as clear identification of our commitment to the customers and markets we serve, and fortifies our brand recognition and presence. Our approach to water management is to manage the lifecycle of a raindrop from the moment water hits the ground until it is released back into the ecosystem. The ADS product portfolio is built around four steps of this lifecycle: Capture, Conveyance, Storage, and Treatment. ADS solutions safely and efficiently manage stormwater with environmentally friendly products. We believe we are the only water management solutions company that manages stormwater from when the rain first hits the ground until the moment it is returned to lakes and streams.

We estimate that the stormwater industry, including landscape irrigation, annually, is an approximately $14 billion industry. We estimate that the onsite wastewater market is a roughly $2 billion industry and that approximately 30% of new North American single-family homes utilize onsite wastewater systems. On a combined basis, we estimate that we have an addressable market opportunity of approximately $16 billion.

For a discussion of segment and geographic information, see “Note 20. Business Segment Information” to our audited consolidated financial statements included in “Item 8. Financial Statements and Supplementary Data” of this Form 10-K.

Following the acquisition of NDS, we realigned our reportable segments to align with the manner in which the Chief Operating Decision Maker (“CODM”) assesses performance and makes resource allocation decisions (the “Segment Realignment”). Our revised reportable segments consist of Stormwater and Wastewater (formerly referred to as the “Infiltrator” reportable segment). Further, we changed the measure used to evaluate segment profitability from adjusted gross profit to Adjusted EBITDA.

Segment results for the historical periods presented in these consolidated financial statements have been recast to reflect these changes. The Segment Realignment had no impact on our previously reported consolidated net sales, income from operations, net income attributable to ADS or earnings per share. These segments are described in greater detail in “Note 20. Business Segment Information” to our audited consolidated financial statements included in “Item 8. Financial Statements and Supplementary Data” of this Form 10-K.

As illustrated in the charts below, we provide a broad range of high performance thermoplastic corrugated pipe and related water management products to a highly diversified set of end markets and geographies.

We design, manufacture and market a complete line of high performance thermoplastic corrugated pipe and related water management products for use in a wide range of end markets. Our product line includes stormwater and wastewater management solution products. Stormwater products are designed as an integrated, end-to-end solution set which provides a comprehensive approach to managing stormwater from the moment it hits the ground until it is cleaned and returned to its natural environment. Stormwater products include single, double and triple wall corrugated polypropylene and polyethylene pipe (“Pipe”); a variety of additional water management products (“Allied Products”), including storm retention/detention and onsite wastewater chambers (“Chambers”); polyvinyl chloride drainage structures (“Structures”); fittings (“Fittings”); water quality filters and separators (“Water Quality”); and NDS channel drains, catch basins and access boxes; and various complementary products distributed through resale agreements, including geotextile products, drainage grates and other products. Wastewater products (formerly referred to as “Infiltrator”) include plastic leachfield chambers and systems, onsite wastewater tanks and accessories.

The table below summarizes the percentage of Net Sales for Stormwater and Wastewater.

Our products and engineering project designs have been continuously and frequently recognized by the industry. This includes being honored many times during the past decade as the Plastics Pipe Institute’s Project of the Year. We have won numerous awards from organizations such as the American Society of Testing & Materials (“ASTM”), the American Society of Civil Engineers, and many others.

Dual Wall Corrugated Pipe - Our N-12 pipe is a dual wall high-density polyethylene (“HDPE”) pipe with a corrugated exterior for strength and a smooth interior wall for hydraulics and flow capacity. Our N-12 pipe competes in the storm sewer and drainage markets that are also served by concrete pipe. Our N-12 pipe is available in a wide range of diameters and sections of length. N-12 provides joint integrity, with integral bell and spigot joints for fast push-together installations and is sold either with watertight or soil-tight coupling and fitting systems. Our corrugated polyethylene pipe offers many benefits including ease of installation, job site handling and resistance to corrosion and abrasion. Corrugated pipe can easily be cut or coupled together, providing precise laying lengths while minimizing installation waste and difficulty.

HP Storm Pipe and SaniTite HP Pipe - Our HP Storm pipe utilizes polypropylene (“PP”) resin, which provides: (i) increased pipe stiffness relative to HDPE; (ii) higher Environmental Stress Crack Resistance; and (iii) improved thermal properties, which improves joint performance. These improved physical characteristics result in a reduced need for select backfill, which creates installation savings for customers and expands the range of possible product applications.

Our SaniTite HP pipe utilizes the same polypropylene resins as our HP Storm pipe but includes a smooth third exterior wall in 30” to 60” pipe. The highly engineered polypropylene resin along with the triple wall design enables SaniTite HP to surpass the stiffness requirement for sanitary sewer applications. SaniTite HP offers cost and performance advantages relative to reinforced concrete pipe (such as improved hydraulics and better joint integrity) and polyvinyl chloride (“PVC”) pipe (such as impact resistance).

Single Wall Corrugated Pipe - Our single wall corrugated HDPE pipe is ideal for drainage projects where flexibility, light weight and low cost are important. Single wall HDPE pipe products have been used for decades in agricultural drainage, highway edge drains, onsite wastewater systems and other construction applications. In the agricultural market, improved technology has highlighted the favorable impact of drainage on crop yields. For homeowners, it is an economical and easily installed solution for downspout run-off, foundation drains, driveway culverts and general lawn drainage. Single wall pipe is also used for golf courses, parks and athletic fields to keep surfaces dry by channeling away excess underground moisture. Standard single wall products are available in a wide range of diameters and sold in varying lengths. Pipe can be either perforated or non-perforated depending on the particular drainage application.

Triple Wall Corrugated Pipe and Smoothwall HDPE Pipe - Our ADS-3000 Triple Wall pipe, small diameter triple wall corrugated pipe, consists of a corrugated polyethylene core molded between a smooth white outer wall and a smooth black inner wall. This combination of the three-wall design adds strength and stiffness, while reducing weight as compared to PVC 2729. Triple Wall is produced and sold through our distribution network. We also manufacture smoothwall HDPE pipe sold into the residential drainage and onsite wastewater systems markets.

We additionally produce a range of Allied Products that are complementary to our Pipe products. Our Allied Products offer adjacent technologies to our core Pipe offering, presenting a complete drainage solution for our clients and customers with this combination forming a key strategy in our sales growth, profitability and market share penetration. The practice of selling a drainage system is attractive to both distributors and end users, by providing a broad package of products that can be sold on individual projects and strengthens our competitive advantage in the marketplace. We aggressively seek and evaluate new products, technologies and regulatory changes that impact our customers’ needs for Allied Products.

The underground construction industry has historically been project (not product) driven, creating the impetus for owners, engineers and contractors to seek manufacturers that deliver solution-based product portfolios. Many of the components of underground construction are related and require linear compatibility of function, regulatory approval and technology.

Storm Chambers - Our StormTech and Cultec chambers are used for stormwater retention, detention and “first flush” underground water storage on residential and non-residential site development along with public projects. These highly engineered chambers are injection molded or thermoformed from HDPE and PP resins into a proprietary design which provides strength, durability, and resistance to corrosion. The chambers allow for the efficient storage of stormwater volume, reducing the underground construction footprint and costs to the contractors, developers, and property owners. The chambers are open bottom, which allows for high density stacking in both storage and shipment. This freight-efficient feature drives favorable cost-competitiveness in serving long-distance export markets. These chamber systems typically incorporate our other product lines such as corrugated pipe, fabricated fittings, water quality units and geotextiles.

Structures - Our Nyloplast PVC drainage structures are used in non-residential, residential and municipal site development, road and highway construction, as well as landscaping, recreational, industrial and mechanical applications. The product family includes inline drains, drain basins, curb inlets and water control structures which move surface-collected stormwater vertically down to pipe conveyance systems. These custom structures are fabricated from sections of PVC pipe using a thermoforming process to achieve exact site-specific hydraulic design requirements. Our Nyloplast products are a preferred alternative to heavier and larger concrete structures, by offering greater design flexibility and improved ease of installation which reduces overall project costs and timelines. The structures incorporate rubber gaskets to ensure watertight connections, preventing soil infiltration which plagues competitive products.

Fittings - We produce fittings and couplings utilizing blow molding, injection molding and custom fabrication on our pipe products. Our innovative coupling and fitting products are highly complementary to our broader product suite and include both soil-tight and water-tight capabilities across the full pipe diameter spectrum. Our fittings are sold in all end markets where we sell our current pipe products.

NDS - The NDS residential product portfolio includes channel drains, catch basins, grates, access boxes, and accessories engineered to capture, convey, and disperse stormwater efficiently. Designed with both performance and aesthetics in mind, NDS products are commonly used in driveways, patios, yards, and landscaped areas to reduce flooding, erosion, and pooling water. With an emphasis on quality materials, code‑compliant designs, and straightforward installation, NDS supports effective stormwater management for everyday residential applications.

NDS channel drains are designed to efficiently capture and redirect surface water away from residential areas, such as driveways, patios, pool decks, and walkways. Featuring a low‑profile, modular design, these drains collect water along their entire length rather than at a single point, helping to prevent pooling and flooding.

NDS catch basins are designed to collect and manage surface water runoff before it can cause flooding, erosion, or damage around residential properties. Installed at low points in landscapes, driveways, or yards, these basins capture rainwater and debris, directing water into underground drainage pipes while trapping sediment to help prevent clogs.

NDS access boxes are designed to provide durable, below‑ground access to a wide range of residential utility components. These boxes are commonly used to protect and organize irrigation valves, water shutoffs, electrical connections, lighting transformers, cleanouts, and other underground service points.

Other Products - Our BioDiffuser, Contactor and Recharger products are chambers that are used in onsite wastewater systems for residential and small volume non-residential wastewater treatment and disposal. The innovative designs of our chambers are generally approved for a footprint reduction, further reducing the cost of the onsite wastewater system. Injection-molded or thermoformed from HDPE or PP, these products are strong, durable, and chemical-resistant. These interconnecting chambers are favored by onsite wastewater contractors because they are lightweight and easy to install.

Our Water Quality product line targets the removal of sediment, debris, oils and suspended solids throughout a stormwater rain event by separating and/or filtering unwanted pollutants.

We purchase and distribute construction fabrics and other geosynthetic products for soil stabilization, reinforcement, filtration, separation, erosion control, and sub-surface drainage. Constructed of woven and non-woven PP, geotextile products provide permanent, cost-efficient site-development solutions. Construction fabrics and geotextiles have applications in all of our end markets.

Our Inserta Tee product line consists of a PVC hub, rubber sleeve and stainless steel band. Inserta Tee is compression fit into the cored wall of a mainline pipe and can be used with all pipe material types and profiles. This product offers an easy tap-in to existing sanitary and storm sewers by limiting the excavation needed for installation compared to competitive products.

The Wastewater reportable segment (formerly referred to as the “Infiltrator” reportable segment) contains the Company’s wholly-owned subsidiary, Infiltrator Water Technologies, LLC (“Infiltrator”). Infiltrator is the leading designer and manufacturer of highly engineered plastic chambers, synthetic aggregate leachfields, combined treatment and dispersal systems, plastic tanks, advanced treatment systems, and related accessories that are used in onsite wastewater systems and decentralized commercial wastewater treatment systems. In addition to the core Wastewater products discussed below, Orenco Systems, Inc. (“Orenco”) was acquired in October of 2024 and added to the Wastewater segment. The onsite wastewater market is heavily reliant on rural homes and communities that do not have access to centralized sewer and will require an onsite wastewater solution. Onsite wastewater technologies are scalable and can easily meet the needs of churches, schools, light commercial and small community construction projects.

Leachfield Products - Our Quick4, Quick5 and ARC line of onsite wastewater leachfield chambers are injection molded using recycled polyolefin materials. There are Quick4, Quick5 and ARC line chamber models available to meet a wide variety of regulatory and market needs. The Quick4, Quick5 and ARC chambers are engineered for strength and performance, easy to install, and offer the user greater design flexibility, including a smaller footprint, as compared with traditional stone and pipe products. The product advantages are cost savings on labor, materials and time savings on the job.

EZflow - EZflow synthetic aggregate bundles replace stone and pipe leachfields for effluent and drainage applications. The EZflow proprietary products are a modular design that incorporates recycled polystyrene aggregate bundles and corrugated polyethylene pipe that act as a replacement to the traditional materials stone and pipe.

Combined Treatment and Dispersal Products - Combined Treatment and Dispersal Products include our AeroFin, Advanced Enviro-Septic (“AES”), Enviro-Septic (“ES”), and Advanced Treatment Leachfield (“ATL”). Our AES and ES systems are proprietary combined treatment and dispersal systems made with a twelve-inch diameter corrugated extrusion product that is encapsulated in fibrous materials and geotextiles. These systems when installed in a bed of sand provide combined treatment and dispersal in the same small footprint and at a reduced cost with minimal long-term maintenance.

Our ATL product is an alternative combined treatment and dispersal system that provides advanced wastewater treatment. The ATL is a profile of polystyrene aggregates and geotextiles installed in a bed of sand. Our AeroFin product is the newest innovation in combined treatment and dispersal systems designed to provide higher treatment within a small footprint reducing installation time and energy.

Tank Products - Our Infiltrator tanks line, including our IM-Series and CM-Series onsite wastewater tanks, are injection or compression molded polypropylene plastic tanks manufactured from recycled materials. Our Infiltrator tanks are available in various capacities for wastewater storage. Our IM-Series is the only two-piece construction, injection molded onsite wastewater tank design in North America. In comparison to traditional concrete tanks, our Infiltrator tanks are easier to transport to the job site and require less time and energy to install.

Our IM-Series line of potable tanks are injection-molded polypropylene plastic tanks manufactured from virgin materials suitable for water reuse and drinking water storage. IM-Series potable tanks are available in various capacities for water storage. IM-Series potable tanks are commonly used in water cistern applications, such as rainwater harvesting systems.

Residential Advanced Treatment Products - Our Advanced Treatment Systems provide a higher level of wastewater purification through mechanical aeration wastewater for residential systems. Our advanced treatment systems product line for residential applications includes ECOPOD, ENVIRO-AIRE, Whitewater, and Orenco Advantex (AX-20 and AX-RT).

Commercial Advanced Treatment Products - Our Advanced Treatment Systems for decentralized and commercial systems are ideal solutions for treatment needs up to 250,000 gallons per day. Our advanced treatment systems product line for commercial applications includes ECOPOD, ENVIRO-AIRE Package Wastewater Treatment Plants, Whitewater, and Advantex Commercial (AX-100 and AX-MAX).

General Onsite Products - We offer a wide assortment of products for general onsite use. These products include Infiltrator EZsnap and EZset risers and lids and secondary tank-riser safety lids. Also included in this category are pump vaults, control panels, pumps, filters, risers, lids, basins, and miscellaneous products from the Orenco general onsite product catalog.

Orenco Controls - Orenco Controls designs and builds more than 20,000 panels a year for residential, commercial, municipal, and original equipment manufacturing (“OEM”) markets. This product line includes pump controllers for Orenco wastewater systems, pump controllers for commercial systems, and OEM controls applications.

Orenco Composites - Orenco Composites use filament winding and two types of closed-molding processes, resin transfer molding and vacuum infusion, to produce fiber-reinforced plastic composite parts. This product line includes large composite tanks, composite utility buildings, treatment plant lids, and custom structures.

Virgin HDPE and PP resins are derivatives of ethylene and propylene, respectively. Ethylene and propylene are derived from natural gas liquids or crude oil derivatives primarily in the U.S. We currently purchase in excess of 1.0 billion pounds of virgin and recycled resin annually from approximately 450 suppliers. As a high-volume buyer of resin, we achieve economies of scale to negotiate favorable terms and pricing. Our purchasing strategies differ based on the material (virgin resin versus recycled material) ordered for delivery to our production locations. The price movements of the different materials also vary, resulting in the need to use strategies to reduce volatility and successfully pass cost increases on to our customers through timely selling price increases when needed.

We have relationships with most of the North American producers of virgin high-density polyethylene and impact copolymer polypropylene producers that manufacture the grades we need to produce our products. The North American capacity for ethylene derivatives has been expanded primarily as a result of supplies of natural gas liquids being produced through sustained oil and gas exploration and production. We anticipate continued growth in the availability of ethylene and propylene which are used to manufacture HDPE and PP, respectively.

We leverage our raw material blending and processing technologies to produce an HDPE pipe that incorporates recycled resin. These products, which meet an ASTM International standard and an American Association of State Highway and Transportation Officials standard, replaces a majority of the virgin resin that is used with optimized recycled materials. The manufacturing of onsite wastewater leach field chambers and tanks leverage these same core competencies in the use of recycled polypropylene material streams. ADS Recycling procures and processes recycled raw materials that can be used in products we produce and sell.

We believe that we are well positioned for future growth as we add additional recycled material processing facilities, add capacity to existing facilities, and expand our supplier base for recycled and virgin resin. In fiscal 2025, we broke ground on a facility expansion at our facility in Cordele, GA that will increase the total facility size to over 110,000 square feet. In October 2024, we opened the $65 million ADS Engineering and Technology Center. The 110,000 square foot research and testing facility, located near our company headquarters, is dedicated to innovation across product engineering, material science and manufacturing technology.

We are one of the largest domestic recyclers of HDPE and PP. We maintain relationships with several of the largest environmental companies which provide us with post-consumer HDPE and PP recycled materials. We also maintain relationships with several key post-industrial HDPE and PP suppliers which provide us with materials that cannot otherwise be utilized in their respective production processes. Further, we are focused on a program of continuous sustainability improvement, with approximately 225 million pounds of post-consumer and post-industrial recycled HDPE and 140 million pounds of post-consumer and post-industrial recycled polypropylene converted each year to make our products. This industry-leading program keeps millions of used bottles out of the landfill and puts them to work again for more than a hundred years as part of our infrastructure. This recycling capacity not only contributes to our sustainability initiatives through the promotion of a circular economy but also allows us to better and more quickly serve the needs of our customers.

We have a leading domestic and international manufacturing and distribution infrastructure, serving customers throughout the United States, Canada, Mexico and other countries worldwide through 64 manufacturing plants and 41 distribution centers, including six manufacturing plants and seven distribution centers owned or leased by our joint ventures.

We manufacture our corrugated pipe products using a continuous extrusion process, where polyethylene or polypropylene is extruded through a die into a moving series of corrugated U-shaped molds. We utilize customized and proprietary production equipment, which we believe produces higher quality final products and is more cost efficient than other pipe making equipment generally available in the market.

Domestically, we can produce more than one billion pounds of pipe annually. Additional capacity is in place to support seasonal production needs and expected growth. Our production equipment is built to accept transportable molds and die tooling over a certain range of sizes, so each plant is not required to house the full range of tooling at any given time. This transportability provides us with the flexibility to optimize our capacity through centrally coordinated production planning, which helps to adapt to shifting sales demand patterns while reducing the capital needed for tooling. With our large manufacturing footprint, we can support rapid seasonal demand growth while focusing on customer service and minimizing transportation costs.

A wide variety of production processes and expertise allow us to provide cost-effective finished goods at competitive prices delivered in a timely fashion to our customers. Our molds and machines have been designed to maximize interchangeability in order to optimize flexibility, maximize efficiency and minimize downtime. The standard fittings products (tees, wyes, elbows, etc.) that we produce and sell to connect our pipe on job sites are blow molded or injection molded at two domestic plants. In addition, customized fabricated fittings (e.g. more complex dual wall pipe reducers, bends or structures) are produced in specific North American plants. We produce storm and onsite wastewater chambers, tanks and accessories using injection molding machines ranging in size.

International Presence - We own manufacturing facilities in Canada to produce our products for sale in the Canadian markets. We serve international markets primarily in Mexico, Central America and South America through joint venture operations with local partners. Our joint venture strategy has provided us with local and regional access to key markets such as Mexico, Brazil, Chile, Argentina, and Peru. Our international joint ventures produce pipe and related products to be sold in their respective regional markets. We also have wholly-owned subsidiaries that distribute our pipe and related products in Europe and the Middle East. Combining local partners’ customer relationships, brand recognition and local management talent, with our world-class manufacturing and process expertise, broad product portfolio and innovation creates a powerful solution driven platform and opportunities for continued profitable international expansion. With the acquisition of NDS, we acquired certain NDS international entities. As discussed in “Note 1. Background and Summary of Significant Accounting Policies,” the NDS International Entities met the held for sale criteria upon acquisition. See “Note 5. Discontinued Operations and Assets and Liabilities Held for Sale” for additional information.

Quality Assurance Control - We have two internal quality assurance control laboratory facilities equipped and staffed to evaluate and confirm incoming raw material and finished goods quality in addition to the quality testing that is done at our manufacturing facilities. We conduct annual safety, product and process quality audits at each of our facilities, using centralized internal resources in combination with external third-party services. In the quality area, various national and international agencies such as Product Evaluation and Audit Solutions, International Association of Plumbing and Mechanical Officials, Bureau de normalisation du Québec, Intertek for Canadian Standards Association, Entidad Mexicana de Acreditacion A.C. and NSF International and several state Departments of Transportation and municipal agencies conduct both scheduled and unscheduled audits/inspections of our plants to verify product quality and compliance to applicable standards.

Fleet - We also operate an in-house fleet of approximately 600 tractors. Our effective shipping radius is approximately 250 miles from one of our manufacturing plants or distribution centers. The combination of a dedicated fleet and team of company drivers allows greater flexibility and responsiveness in meeting dynamic customer job site delivery expectations. We strive to achieve less than three-day lead-time on deliveries and have the added benefit of redeploying fleet and driver assets to respond to short-term regional spikes in sales activity. For deliveries that are outside an economic delivery radius of our truck fleet, common carrier deliveries are tendered to a third-party to ensure that lowest delivered freight costs are achieved while maintaining high levels of customer service. In addition, in line with our commitment to sustainability, we are continuously upgrading our tractors with state-of-the-art safety features, fuel economy, and digital technology to attract the driver of the future, reduce our total emissions and keep our drivers safe on and off the road.

Our North American truck fleet incorporates approximately 1,100 trailers that are specially designed to haul our lightweight pipe and Allied Products. These designs maximize payload versus conventional over the road trailers and facilitate the loading and unloading of our products at the various customer delivery locations. The trailer design assists in managing the fuel efficiency of our fleet by decreasing total trailer weight and aerodynamic design. The scope of fleet operations also includes backhaul throughout our network to lower our total delivered cost and increase our asset utilization.

Facility Network - Our scale and extensive network of Pipe and Allied Products facilities provide a critical cost advantage versus our competitors, as we are able to more efficiently transport products to our customers and end users and to promote faster product shipments due to our proximity to the delivery location. The optimized design of our onsite wastewater chambers and tanks provides the ability to nest products, enabling us to manufacture products from one location and efficiently ship throughout North America.

“Our Reason is Water” and our vision is to advance the quality of life through sustainable solutions to water management challenges. We are dedicated to providing clean water management solutions to communities and delivering unparalleled service to our customers. Our commitment to sustainability was recognized when we were first named on Newsweek’s list of America’s Most Responsible Companies in 2024.

We are focused on bringing highly engineered products to market that are both sustainable and resilient. These products assist our customers in meeting sustainability targets such as LEED or ENVISION certification while also allowing them to make needed repairs to aging infrastructure, plan for and mitigate future impacts from climate change and rapidly recover from catastrophic events when necessary. Our manufacturing facilities have no material process-related by-products released into the atmosphere, waterways, or solid waste discharge. During pipe production start-ups and size changeovers, non-compliant scrap and any damaged finished goods pipe are recycled for internal re-use.

In fiscal 2022, we announced our 10 Year Sustainability Goals, which are available on our website. The goals are a set of targets focused on the “REASON” in “Our Reason is Water” and demonstrate our commitment to leadership in environment, social and governance. The goals include: a commitment to increase our use of recycled plastic, a commitment to operation clean sweep for plastic pellet management, implementing a supplier sustainability program, reducing our total recordable injury rate, implementing closed-loop water usage at all our manufacturing locations, continuing our efforts in culture and employee engagement and maintaining transparency in our sustainability reporting efforts. The goals are not included as part of, or incorporated by reference, into this Annual Report on Form 10-K.

We believe we have one of the largest and most experienced sales and engineering forces in the industry. Offering the broadest product line in the industry enables our sales force to source the greatest number of new opportunities and more effectively cross-sell products than any of our competitors. We consistently maintain thousands of touch points with customers, civil engineers and municipal authorities, continuously educating them on new product innovations and their advantages relative to traditional products. We believe we are the industry leader in these efforts, and we view this work as an important part of our marketing strategy, particularly in promoting N-12 and SaniTite HP for storm and sanitary sewer systems, as regulatory approvals are essential to the specification and acceptance of these product lines.

Our sales and marketing strategy is divided into four components: comprehensive market coverage, diverse product offerings, readily-available local inventory and specification efforts. Our goal is to provide the distributor/owner with the most complete, readily available product line in our industry. We strive to use our manufacturing footprint, product portfolio and market expertise to efficiently service our customers.

Our sales and engineering objective is to influence, track and quote all selling opportunities as early in the project life cycle as possible. We strive to be meaningfully involved in all phases of the project cycle, including design, bidding, award and installation. Conceptual project visibility allows sales and engineering professionals the ability to influence design specifications and increase the probability of inclusion of our products in bid documents. The inclusion of our products in bid documents improves the probability of completing the sale. On-demand installation support allows us to maintain customer relationships and ensure positive installation experience. In addition to direct channel customers, we also maintain and develop relationships with federal agencies, municipal agencies, national standard regulators, private consulting engineers and architects. Our consistent interaction with these market participants enables us to continue our market penetration. This ongoing dialogue has positioned us as an industry resource for design guidance and product development and as a respected expert in water management solutions.

NDS goes to market through a multi‑channel distribution strategy focused on reaching both professionals and homeowners. Its primary customers include landscape contractors, irrigation installers, builders, and engineers, as well as DIY consumers. NDS products are sold through wholesale distribution partners such as landscape supply yards and irrigation distributors, along with national home improvement retailers and online channels. By supporting professional specifiers while also making products accessible at retail, NDS effectively serves a broad residential stormwater market with solutions designed for both trade and consumer use.

We have a large, active customer base of approximately 16,000 customers, with two customers representing 10% or more of fiscal 2026 net sales. Ferguson Enterprises (“Ferguson”) accounted for 13.1% and Core & Main, Inc. (“Core & Main”) accounted for 12.8% of fiscal 2026 net sales. Our customer base is diversified across the range of end markets that we serve.

A majority of our sales are made through distributors, including many of the largest national and independent waterworks distributors, with whom we have long-standing distribution relationships and who sell primarily to the storm sewer and sanitary sewer markets. We also utilize a network of hundreds of small to medium-sized independent distributors across the United States. We have strong relationships with major national retailers that carry drainage products. We offer the most complete line of HDPE products in the industry and are the only national manufacturer that can service the “Big-Box” retailers from coast-to-coast. We also sell to buying groups and co-ops in the United States that serve the plumbing, hardware, irrigation and landscaping markets. Selling to buying groups and co-ops provides us with a further presence on a national, regional and local basis for the distribution of our products. Our preferred vendor status with these groups allows us to reach thousands of locations in an effective manner. Members of these groups and co-ops generally are independent businesses with strong relationships and brand recognition with smaller contractors and homeowners in their local markets. The combination of our large sales force, long-standing retail and contractor customer relationships and extensive network of manufacturing and distribution facilities complements and strengthens our broad customer and market coverage.

Our customer service organization is supplemented by the employees of our manufacturing plants, distribution centers and drivers of our tractor-trailers. In conjunction with our field sales and engineering team, this highly trained and competent staff allows us to maintain more customer touch points and interaction than any of our competitors.

Historically, sales of our products have been higher in the first and second quarters of each fiscal year due to favorable weather and longer daylight conditions accelerating construction activity during these periods. Seasonal variations in operating results may also be impacted by inclement weather conditions, such as cold or wet weather, which can delay projects. In the non-residential, residential and infrastructure markets in the northern United States and Canada, construction activity typically begins to increase in late March and is slower in December, January and February. In the southern and western United States, Mexico, Central America and South America, the construction markets are less seasonal. The agricultural drainage market is concentrated in the early spring just prior to planting and in the fall just after crops are harvested prior to freezing of the ground in winter.

We operate in a highly fragmented industry and hold leading positions in multiple market sectors. Competition, including our competitors and specific competitive factors, varies for each market sector. Our products are generally lighter, more durable, more cost effective and easier to install than comparable alternatives made with traditional materials. Following our entrance into the non-residential construction market with the introduction of N-12 corrugated HDPE pipe in the late 1980s, our pipe has been displacing traditional materials, such as reinforced concrete, corrugated steel and PVC, across an ever-expanding range of end markets, including non-residential, residential, agriculture and infrastructure applications. In the United States, our nationwide footprint combined with our strong local presence and broad product offering make us the leader in an otherwise highly fragmented sector comprised of many smaller competitors.

We believe the principal competitive factors for our market sectors include local selling coverage, product availability, breadth and cost of products, technical knowledge and expertise, customer and supplier relationships, reliability and accuracy of service, effective use of technology, delivery capabilities and timeliness, pricing of products, and the provision of credit. We believe that our competitive strengths and strategy allow us to compete effectively in our market sectors.

The stormwater drainage industry, in particular, is highly fragmented with many smaller specialty and regional competitors providing a variety of product technologies and solutions. We compete against concrete pipe, corrugated steel pipe and PVC pipe producers on a national, regional and local basis. In addition, there are many HDPE pipe producers in the United States.

We believe we are the only corrugated HDPE pipe producer with a national footprint, and our competitors operate primarily on a regional and local level.

We rely upon a combination of patents, trademarks, trade names, licensing arrangements, trade secrets, know-how and proprietary technology in order to secure and protect our intellectual property rights, both in the United States and in foreign countries.

We seek to protect our new technologies with patents and trademarks and defend against patent infringement allegations. We hold a significant amount of intellectual property rights pertaining to product patents, process patents and trademarks. We continually seek to expand and improve our existing product offerings through product development and acquisitions. Although our intellectual property is important to our business operations and in the aggregate constitutes a valuable asset, we do not believe that any single patent, trademark or trade secret is critical to the success of our business as a whole. We cannot be certain that our patent applications will be issued or that any issued patents will provide us with any competitive advantages or will not be challenged by third parties.

In addition, we generally control access to and use of our proprietary and other confidential information through the use of internal and external controls, including contractual protections with employees, distributors and others. See “Item 1A. Risk Factors - Risks Relating to Our Business - If we are unable to protect our intellectual property rights, or we infringe on the intellectual property rights of others, our ability to compete could be negatively impacted.”

At the core of the Company’s history are the people, many of whom have been with the Company for several decades. We are dedicated to fostering a culture that empowers employees and communities by embracing the dynamics of different backgrounds, experiences and perspectives. We are committed to creating an environment where employees feel valued, respected, and fully engaged to contribute to our future success. The ability to recruit, retain, develop and protect our global workforce is key to our success. In addition to providing competitive compensation and benefits, this includes the following categories: Health and Safety; Values; and Training.

Employees - As of March 31, 2026, in our domestic and international operations, the Company and its consolidated subsidiaries had both hourly personnel and salaried employees. As of March 31, 2026, approximately 100 hourly personnel in our Mexican joint venture were covered by collective bargaining agreements.

We base hiring and promotional decisions on job qualifications, such as work records, performance history and length of service, to ensure equal opportunity to all. We also ensure equal opportunity across all relevant aspects of employment such as recruiting, job assignment, compensation, benefits, transfers, promotional opportunities, Company sponsored training, and recreation programs, among others.

Health and Safety - Employee safety is our highest priority and a key component of our company culture. Our operations follow a comprehensive, proactive safety and health management system that includes a collaborative process to find and fix workplace hazards prior to injury occurrence. Our U.S. facilities follow the Occupational Safety and Health Act safety and health general industry standards under the Department of Labor and Federal Motor Carrier Safety Administration under the Department of Transportation, as required by law; our Canadian facilities follow the Canada Occupational Health and Safety Regulations under the Canada Labour Code for the Minister of Labour and Canada Motor Vehicle Safety Standards under Transport Canada as required by law; and our Mexico locations follow the NOMs as required by the Federal Labor Law for the Labor Ministry and Secretary of Communication and Transportation as required by law.

Values - Our success as a company is built on the Honesty, Professionalism, and Core Values of our employees, directors, and agents. These three tenets serve as the guiding principles of our Code of Business Conduct and Ethics (the “Ethics Code”).

•Honesty: We believe in always being honest in dealing with our customers, suppliers, and others and complying with all laws and regulations applicable to our business at all levels.

•Professionalism: We believe in providing our products and services in a prompt and professional manner, gaining the loyalty and trust of our customers and suppliers.

•Core Values: We believe in certain “core values” centered upon ensuring quality throughout our product and organization for long-term growth and profitability.

The Ethics Code provides a framework by which we maintain the highest ethical standards in the conduct of our business and is an integral part of implementing our vision of ethically and sustainably maximizing value. All members of our organization are expected to adhere to each of the policies of the Ethics Code, while also employing good ethical judgment. The Ethics Code provides guidelines in relation to conflicts of interest, fair dealing, confidential information and intellectual property, fair employment practices, environmental health and safety, and improper payments to third parties, among many other areas of ethical business conduct.

Training - Our operational and management training programs are core to our commitment and enablement of a safe and productive manufacturing environment. Through our ADS Academy, we deliver targeted role-specific training to our operations team members through a blended curriculum of online and hands-on training experiences covering safety, quality, product knowledge and manufacturing process. Our learning management system serves as the foundation of our operational training programs and provides us with appropriate scale, efficiency, and governance to support our growth. We have a strong commitment to the training of our manufacturing supervisors and managers in technical, management, and leadership subjects through intense role-based assimilation plans, e-learning and classroom-based development experiences.

Our operations are affected by various statutes, regulations and laws in the markets in which we operate, which historically have not had a material effect on our business. We are subject to various laws applicable to businesses generally, including laws affecting land usage, zoning, the environment, health and safety, transportation, labor and employment practices, competition, immigration and other matters. Additionally, building codes may affect the products our customers are allowed to use, and, consequently, changes in building codes may affect the salability of our products. The transportation and disposal of many of our products are also subject to federal regulations. We are subject to safety requirements governing interstate operations prescribed by the U.S. Department of Transportation (“U.S. DOT”). Vehicle dimensions and driver hours of service also remain subject to both federal and state regulation.

We have been able to consistently capitalize on changes in both local and federal regulatory statutes relating to storm and sanitary sewer construction, repair and replacement. Most noteworthy is the Federal Clean Water Act of 1972 and the subsequent U.S. Environmental Protection Agency Phase I, II and sustainable infrastructure regulations relating to storm sewer construction, stormwater quantity, stormwater quality, and combined sewer separation. Our diversity of products offering a solution-based selling approach coupled with detailed market knowledge makes us an integral industry resource in both regulatory changes and compliance.

An important element of our growth strategy has been our focus on industry education efforts to drive regulatory approvals for our core HDPE products at national, state and local levels. We employ field-based engineers who work closely with government agencies to obtain regulatory approvals for our products, and also with civil engineering firms to specify our products on non-residential construction and road-building projects. Additional state and local regulatory approvals will continue to present new growth opportunities in new and existing geographic markets for us. The trend of substituting traditional materials for HDPE and PP is expected to continue as more states and municipalities recognize the benefits of our HDPE N-12 pipe and our polypropylene HP pipe by approving it for use in a broader range of applications.

Our onsite wastewater and decentralized wastewater treatment systems cannot be sold without regulatory approval. We have a dedicated regulatory team with a track record of gaining favorable regulatory approvals and advancing policy and legislation. Over the past 10 years, the team has successfully embarked in over 100 regulatory initiatives increasing the addressability and size of markets across the U.S. and Canada.

We are subject to a broad range of foreign, federal, state and local environmental, health and safety laws and regulations, including those pertaining to air emissions, water discharges, the handling, disposal and transport of solid and hazardous materials and wastes, the investigation and remediation of contamination and otherwise relating to health and safety and the protection of the environment and natural resources. To a limited extent, our current and past operations, and those of many of the companies we have acquired, involve materials that are, or could be classified as, toxic or hazardous. There is an inherent risk of contamination and environmental damage in our operations and the products we handle, transport and distribute. See “Item 1A. Risk Factors — Risks Relating to Our Business — We could incur significant costs in complying with environmental, health and safety laws or permits or as a result of satisfying any liability or obligation imposed under such laws or permits.”

Information about the Company’s working capital practices is incorporated herein by reference to “Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations” of this Form 10-K.

We were founded in 1966 and are a Delaware corporation. Our principal executive offices are located at 4024 Green Stripe Lane, Hilliard, Ohio 43026, and our telephone number at that address is (800) 733-7473. Our corporate website is www.adspipe.com.

Our Annual Report on Form 10-K, Quarterly Reports on Form 10-Q, Current Reports on Form 8-K, and amendments to reports filed pursuant to Sections 13(a) and 15(d) of the Securities Exchange Act of 1934, as amended, (“Exchange Act”) are filed with the SEC. We are subject to the informational requirements of the Exchange Act and file or furnish reports, proxy statements, and other information with the SEC. Such reports and other information filed by the Company with the SEC are available free of charge on our website at www.adspipe.com when such reports are available on the SEC’s website. We use our www.adspipe.com website as a means of disclosing material non-public information and for complying with our disclosure obligations under Regulation FD. Accordingly, investors should monitor such portions of www.adspipe.com in addition to following press releases, SEC filings and public conference calls and webcasts. The contents of the websites are not incorporated into this filing. Further, our references to these websites are intended to be inactive textual references.

Resin prices fluctuate substantially as a result of changes in crude oil and natural gas prices, changes in existing processing capabilities and the capacity of resin suppliers. Polypropylene resin suppliers are limited, high-density polyethylene suppliers are geographically concentrated, and supply of recycled resin is also limited. Supply interruptions could arise from disruptions to existing petrochemical capacity and recycled resin sources caused by labor disputes and shortages, weather conditions or natural disasters affecting supplies or shipments, transportation disruptions or other factors beyond our control. An extended disruption in the timely availability of raw materials from our key suppliers would result in a decrease in our revenues and profitability. Additionally, our customers’ production schedules could be impacted by these shortages, which could result in reduced sales of our products.

Inflation in these raw material costs could also result in significant cost increases, further affecting our business. Our ability to maintain profitability heavily depends on our ability to pass through to our customers any increase in raw material costs. If increases in the cost of raw materials or any potential tariffs cannot be passed on to our customers, our business, financial condition, results of operations and cash flows will be adversely affected. Conversely, in the event that there is deflation, we may experience pressure from our customers to reduce prices. We may not be able to reduce our cost base to offset any such price concessions which could adversely impact our results of operations and cash flows.

The markets in which we operate are sensitive to regional, U.S. and worldwide economic conditions, including availability of credit, interest rates, inflation, tariffs or other trade policies, fluctuations in capital and business and consumer confidence. The difficult conditions in these markets and the overall economy affect our business in a number of ways. For example:

•The volatility of the U.S. economy, including market uncertainty and volatility, can have an adverse effect on our sales that are dependent on the non-residential construction market if participants in this industry may postpone spending or are otherwise unable to secure financing for construction projects.

•Our business depends upon general activity levels in the agriculture market. The nature of the agriculture market is such that a downturn in demand can occur suddenly, resulting in excess inventories, underutilized production capacity and reduced prices for pipe products.

•Shifts in residential housing trends (urban vs. suburban), homeowner demographics, increasing mortgage rates, and consumers ability to finance home construction impact demand for our products.

•Demand for our products and services depends to a significant degree on spending on infrastructure. Infrastructure spending is affected by a variety of factors beyond our control, including interest rates, inflation, availability and commitment of public funds for municipal spending and highway spending and general economic conditions.

Additionally, U.S. policies related to global trade and tariffs could have a material adverse effect on our results of operations. The current administration has suggested various new strategies regarding tariffs. In response, countries have imposed or proposed additional tariffs on certain U.S. imports, as well as additional trade restrictions. Tariffs may result in a decrease of global trade volumes due to uncertainty, may create an administrative burden and will cause companies to make difficult decisions as to how to pay the tariffs or absorb the cost into their profit margins.

Weakness in the markets in which we operate could have a material adverse effect on our business, financial condition, results of operations and cash flows. Bank failures and market disruptions could impact banks used by our customers, which could negatively affect our customers. Delays in the placement of new orders and extended uncertainties may reduce future sales of our products and services. The revenue growth and profitability of our business depend on the overall demand for our product and services. We may have to close under-performing facilities as warranted by general economic conditions and/or weakness in the markets in which we operate. In addition to a reduction in demand for our products, these factors may also reduce the price we are able to charge for our products and restrict our ability to pass on raw material cost increases to our customers. This, combined with an increase in excess capacity, will negatively impact our profitability, cash flows and our financial condition, generally.

Competitors may have financial and other resources that are greater than ours and may be better able to withstand price competition and inflationary pressures. In addition, consolidation by industry participants could result in competitors with increased market share, larger customer bases, greater diversified product offerings and greater technological and marketing expertise, which would allow them to compete more effectively against us. Moreover, our competitors may develop products that are superior to our products or may adapt more quickly to new technologies or evolving customer requirements or requests. In many markets in which we operate, there are no significant entry barriers that would prevent new competitors from entering the market, especially on the local level, or existing competitors from expanding in the market. Increased competition by existing and future competitors could result in reductions in sales, prices, volumes and gross margins that would materially adversely affect our business, financial condition, results of operations and cash flows. Furthermore, our success will depend, in part, on our ability to maintain our market share, generate adequate demand for our products and gain market share from competitors.

Many of our products are made from a material whose manufacturing process involves the emission of carbon dioxide, a greenhouse gas (“GHG”) that scientists have attributed as a cause of climate change. Our products require transportation from our facilities to the site where they are used, which consumes energy. Concerns over climate change, including the impact of global warming, has led to federal, state, and international efforts to limit GHG emissions. Although it is uncertain what actions various governmental bodies will take to address the effects of climate change and to achieve goals in response to the effects of climate change, including in what timeframe those actions would be implemented, new laws or regulations could directly and indirectly affect our customers and suppliers (through an increase in the cost of production or their ability to produce satisfactory products) and our business (through the impact on our inventory availability, cost of sales, operations or demands for the products we sell).

Until the timing, scope and extent of any regulation becomes known, we cannot predict its effect on our cost structure or our operating results, but it is likely our costs will increase in relation to any climate change legislation and regulations concerning GHG, which could have an adverse effect on our future financial position, results of operations or cash flows.

In January 2022, we communicated our initial 10-year goals regarding sustainability. To reduce our environmental impact, we have committed to pursuing science-based targets consistent with limiting global temperature increase to 1.5°C above pre-industrial levels. We are working to define absolute targets for reduction of scope 1 (direct) & 2 (indirect) greenhouse gas emissions that align with limiting future temperature rise to 1.5°C above baseline. These goals reflect our current plans and there is no guarantee that they will be achieved. Our ability to achieve any goal is subject to factors and conditions, many of which are outside of our control, including technology, or the availability of recycled resin.

While we no longer face reporting requirements under SEC rules after the SEC stated it would no longer defend its previous rules on climate-related disclosures, we may be subject to reporting requirements as states enact reporting obligations. Regardless of whether governmental bodies enact legislation to address climate change and reduce GHG emissions or we achieve our 10-year goals, the public perception of carbon-intensive industries may change adversely over time and additional focus on environmental, social and governance issues by the public and/or investors may harm our business as it could damage our reputation, require us to expend resources in reducing our net carbon emissions, or reduce demand for our products, which could adversely impact our results of operations and cash flows.

Most of our business units experience seasonal variation as a result of the dependence of our customers on suitable weather to engage in construction projects. Generally, during the winter months, construction activity declines due to inclement weather, frozen ground and shorter daylight hours. In addition, to the extent that hurricanes, severe storms, floods, other natural disasters or similar events occur in the geographic regions in which we operate, our results of operations may be adversely affected. We anticipate that fluctuations of our operations results from period to period due to seasonality will continue in the future.

Notwithstanding our commitment to advancing sustainable business practices, climate change may also have adverse physical or financial impacts on our business to the extent that it causes more severe or more frequent major storm events, flooding, drought-induced wildfires, or other shifts in weather patterns. Increases in the intensity and frequency of acute weather events have been linked to climate change, and this risk may increase to the extent global warming continues or is unabated. These types of extreme weather events may include disruptions to operations or production, disruptions to supply chains or damage to our physical plants, which could lead to reduced financial performance of our business.

Our success will depend, in part, on our ability to maintain the quality of our customer service, and selling and marketing efforts, as well as our ability to develop long-term relationships with our customers. Our ten largest customers generated approximately 50% of our net sales in fiscal 2026. Because we do not have long-term arrangements with many of our customers, such customers may cease purchasing our products without notice or upon short notice to us. In addition, consolidation among customers could also result in a loss of some of our present customers to our competitors. The loss of one or more of our significant customers, a significant customer’s decision to purchase our products in significantly lower quantities than they have in the past, or deterioration in our relationship with any of them could have a material adverse effect on our business, financial condition, results of operations and cash flows.

The majority of our net sales volume is facilitated through the extension of credit to our customers whose ability to pay is dependent, in part, upon the economic strength of the industry in the areas where they operate. The inability of our customers to pay in a timely manner, or at all, would adversely affect our business, financial condition, results of operations and cash flows. Furthermore, our collections efforts with respect to non-paying or slow-paying customers could negatively impact our customer relations going forward.

Our operations are working capital intensive, and our inventories, accounts receivable and accounts payable are significant components of our net asset base. We manage our inventories and accounts payable through our purchasing policies and our accounts receivable through our customer credit policies. If we fail to adequately manage our supply purchasing or customer credit policies, our working capital and financial condition may be adversely affected.

Our international operations are subject to risks similar to those affecting our operations in the U.S. in addition to a number of other risks, including: difficulties in enforcing contractual and intellectual property rights; impositions or increases of withholding and other taxes on remittances and other payments by subsidiaries and affiliates; difficulties in managing and complying with continually evolving data and privacy laws, such as the European Union’s General Data Protection Regulation and a number of state-specific consumer privacy laws in the U.S.; exposure to different or changing legal standards, including potential changes in government mandated regulatory product standards in those countries in which we or our joint ventures operate; fluctuations in currency exchange rates; impositions or increases of investment and other restrictions by foreign governments; the requirements of a wide variety of foreign laws; political and economic instability; war, escalating geopolitical conflicts or acts or threats of terrorism; and difficulties in staffing and managing operations, particularly in remote locations.

The U.S. Foreign Corrupt Practices Act and similar foreign anti-corruption laws generally prohibit companies and their intermediaries from making improper payments or providing anything of value to wrongfully influence foreign government officials for the purpose of obtaining or retaining business or obtaining an unfair advantage, and generally require companies to maintain accurate books and records and internal controls, including at foreign controlled subsidiaries. Our internal policies provide for compliance with all applicable anti-corruption laws for both us and for our joint venture operations. Our continued operation and expansion outside the U.S., including in developing countries, could increase the risk of such violations in the future. Despite our training and compliance programs, our internal control policies and procedures may not always protect us from unauthorized, reckless or criminal acts committed by our employees, agents or joint venture partners.

With respect to our existing joint ventures, any differences in views among the joint venture participants may result in delayed decisions or in failures to agree on major issues. We also cannot control the actions of our joint venture partners, including any nonperformance, default or bankruptcy of our joint venture partners. We may be unable to control the quality of products produced by the joint ventures or achieve consistency of product quality as compared with our other operations. In addition to net sales and market share, this may have a material negative impact on our brand and how it is perceived thereafter. Moreover, if our partners also fail to invest in the joint venture in the manner that is anticipated or otherwise fail to meet their contractual obligations, the joint ventures may be unable to adequately perform and conduct their respective operations, requiring us to make additional investments or perform additional services to ensure the adequate performance and delivery of products and/or services to the joint ventures’ customers, which could have a material adverse effect on our business, financial condition, results of operations and cash flows.

We may develop new products and processes based on our existing manufacturing, design and engineering capabilities and services. Our business depends in part on our ability to identify future products and product lines that complement existing products and product lines and that respond to our customers’ needs. We may not be able to compete effectively unless our product selection keeps up with trends in the markets in which we compete or trends in new products. In addition, our ability to integrate new products and product lines into our distribution network could impact our ability to compete. Furthermore, the success of new products and new product lines will depend on market demand and there is a risk that new products and new product lines will not deliver expected results, which could negatively impact our future sales and results of operations.

Our financial performance and future growth depend on our management’s ability to successfully implement our initiatives. Our operational initiatives are focused on customer experience, capacity expansion, automation, safety, order management and transportation. Automation in our plants will allow for production efficiency and improved safety for plant personnel. Any failure to successfully implement these initiatives and related strategies could adversely affect our business, financial condition, and results of operations, including increases in our severance and impairment charges.

Prices and availability of petroleum products are subject to political, economic and market factors that are outside our control. We consume a large amount of energy and petroleum products in our operations, including the manufacturing process and delivering products to our customers by our in-house fleet. The recent conflict in the Middle East has led to an increase in oil prices in the U.S. Oil prices may continue to surge if the conflict continues, other geopolitical conflicts arise or continue, certain oil supply routes remain blocked or additional supply routes become blocked. While we utilize a diesel hedging program associated with our in-house fleet to mitigate against higher fuel prices, our operating profit will be adversely affected if we are unable to obtain the energy and fuel we require or to fully offset the anticipated impact of higher energy and fuel prices through increased prices or surcharges to our customers or through other hedging strategies. If shortages occur in the supply of energy or necessary petroleum products and we are not able to pass along the full impact of increased energy or petroleum prices to our customers, our business, financial condition, results of operations and cash flows would be adversely affected.

We internally manufacture our own products at our facilities with substantial fixed costs. While we maintain insurance covering our facilities and have significant flexibility to manufacture and ship our own products from various facilities, a loss of the use of our facilities, whether short or long-term, could have a material adverse effect on our business, financial condition, results of operations and cash flows. Our business interruption insurance may not be sufficient to offset the lost revenues or increased costs that we may experience during a disruption of our operations.

Unexpected failures of our equipment and machinery may result in production delays, revenue loss and significant repair costs, injuries to our employees, and customer claims. Increasing manufacturing capacity requires successful execution of capital projects, including adding, upgrading and replacing equipment, which may be subject to supply chain delays for equipment or parts. Global supply chain disruptions and the related impacts on our third-party suppliers to deliver the raw materials, components, systems and parts that we need to manufacture and service our products could also adversely impact our production. Any interruption in production may limit our ability to supply enough products to customers and may require us to make capital expenditures, which could have a negative impact on our profitability and cash flows.

We are exposed to construction defect and product liability claims relating to our various products if our products do not meet customer expectations. Such liabilities may arise out of the quality of raw materials we purchase from third-party suppliers. We also operate a large fleet of trucks and other vehicles and therefore face the risk of traffic accidents. We cannot make assurances that our insurance will provide adequate coverage against claims or that we will be able to obtain such insurance on acceptable terms in the future, if at all.

From time to time, we are also involved in government inquiries and investigations, as well as consumer, employment, tort proceedings and other litigation. We cannot predict with certainty the outcomes of these legal proceedings and other contingencies. The outcome of some of these legal proceedings and other contingencies could require us to take actions which would adversely affect our operations, negatively impact customer confidence in us and our products or could require us to pay substantial amounts of money. Additionally, defending against these lawsuits and proceedings may involve significant expense and diversion of management’s attention and resources from other matters.

While we are not engaged in a regulated industry, we are subject to various laws applicable to businesses generally, including laws affecting land usage, zoning, the environment, health and safety, transportation, labor and employment practices (including pensions), competition, immigration and other matters. Approvals by municipalities, the U.S. and state departments of transportation, engineers and developers may affect the products our customers are allowed to use, and, consequently, failure to obtain or maintain such approvals may affect the salability of our products. Building codes may also affect the products our customers use, and, consequently, changes in building codes may also affect the salability of our products. Changes in applicable regulations governing the sale of some of our products, including changes in government-mandated regulatory product standards in countries in which we or our joint ventures operate, could increase our costs.

In addition, changes to applicable tax laws and regulations could increase our costs of doing business. We may incur material costs or liabilities in connection with regulatory requirements.

We deliver products to many of our customers through our own fleet of vehicles. The U.S. DOT regulates our operations in domestic interstate commerce. Vehicle dimensions and driver hours of service are subject to both federal and state regulation. More restrictive limitations on vehicle weight and size, trailer length and configuration, or driver hours of service could increase our costs, which, if we are unable to pass these cost increases on to our customers, would reduce our gross profit and net income (loss) and increase our selling, general and administrative expenses.

We cannot predict whether future developments or changes in law, regulations or government mandated product standards will affect our business, financial condition and results of operations in a negative manner. Similarly, we cannot assess whether we will be successful in meeting future demands of regulatory agencies in a manner which will not materially adversely affect our business, financial condition, results of operations and cash flows.

Because we use our information technology (“IT”) systems to, among other things, manage inventories and accounts receivable, make purchasing decisions and monitor our results of operations, the proper functioning of our IT systems is important to the successful operation of our business. Although our IT systems are protected through physical and software safeguards and remote processing capabilities exist, IT systems are still vulnerable to natural disasters, power losses, unauthorized access, telecommunication failures and other problems. If critical IT systems fail, or are otherwise unavailable, our ability to process orders, track credit risk, identify business opportunities, maintain proper levels of inventories, collect accounts receivable and pay expenses and otherwise manage our business units would be adversely affected.

Management uses IT systems to support decision making and to monitor business performance. We may fail to generate accurate financial and operational reports essential for making decisions at various levels of management. In addition, if we do not maintain adequate controls such as reconciliations, segregation of duties and verification to prevent errors or incomplete information, our ability to operate our business could be limited.

We have made, and will continue to make, significant investments in technology. Our technology initiatives are designed to provide our customers a better order management and fulfillment experience, streamline our manufacturing operations and improve the quality of our internal control environment. The cost and potential problems and interruptions associated with the implementation of our technology initiatives could disrupt or reduce the efficiency of our operations in the near term. In addition, our new or upgraded technology might not provide the anticipated benefits, might take longer than expected to realize the anticipated benefits or might fail altogether. The occurrence of such issues could have a material adverse effect on our business financial condition and results of operations.

In the conduct of our business, we collect, use, transmit and store data on information systems, which are vulnerable to

disruption and an increasing threat of continually evolving cybersecurity risks. Cybersecurity incidents across industries are sophisticated and frequent and may range from uncoordinated individual attempts to targeted measures. These incidents include but are not limited to, malicious software or viruses, including “ransomware” attempts to gain unauthorized access to, or otherwise disrupt, our information systems, attempts to gain unauthorized access to business, proprietary or other confidential information, and other electronic security breaches that could lead to disruptions in critical systems, unauthorized release of confidential or otherwise protected information and corruption of data. New developments in the fields of generative artificial intelligence (“AI”), machine learning, and robotics may create new vulnerabilities and cybersecurity risks. Cybersecurity failures may be caused by employee error, malfeasance, other corporate or governmental actors, system errors or vulnerabilities, including vulnerabilities of our vendors, suppliers, and their products.

While we have been subject to cybersecurity incidents in the past that (based on information known to date) did not have a material impact on our financial condition or results of operations, we may experience such incidents in the future, potentially with more frequency or sophistication which may have a material impact on our financial condition or results of operations. The occurrence of any of these events could adversely affect our reputation and could result in litigation, regulatory action, financial loss, project delay claims and increased costs and operational consequences of implementing further data protection systems.

Failures of our IT systems as a result of cybersecurity incidents or other disruptions could result in a breach of critical operational or financial controls and lead to a disruption of our operations, commercial activities or financial processes. Cybersecurity incidents or other disruptions impacting significant customers and/or suppliers could also lead to a disruption of our operations. Given the persistent and advanced nature of cybersecurity threats, we continue to invest in upgraded programs, implement advanced features, and establish adequate controls to stop or curtail these threats. However, investing in upgraded programs, advanced features and adequate controls is expensive and an ongoing, rapidly changing challenge. Further, our attempts to safeguard our systems and mitigate potential risks may not be sufficient to prevent cyberattacks or security breaches that manipulate or improperly use our systems or networks, compromise confidential or otherwise protected information, destroy or corrupt data, or otherwise disrupt our operations. The occurrence of such events could have a material adverse effect on our business financial condition, reputation and results of operations.

All of these risks are also applicable when we rely on outside vendors to provide services. We are dependent on third-party vendors to operate secure and reliable systems which may include data transfers over the internet. Any events which deny us use of vital operating or information systems may seriously disrupt our normal business operations. Additionally, our key partners, distributors or suppliers could experience a compromise of their information security due to a cybersecurity incident, which may have an impact on our business, reputation and financial performance.

To be successful, we must attract, train and retain a large number of highly qualified employees while controlling related labor costs. Our ability to control labor costs is subject to numerous external factors, including prevailing wage rates and health and other insurance costs. The market for highly qualified employees remains competitive and may not be able to attract or retain highly qualified employees in the future, including those employed by companies we acquire. None of our domestic employees are currently covered by collective bargaining or other similar labor agreements. However, if a number of our employees were to unionize, the effect on us may be negative. Additionally, we increasingly compete for talent within our industry.

In addition, our business results of operations depend largely upon our chief executive officer and senior management team as well as our plant managers and sales personnel, including those of companies acquired, and their experience, knowledge of local market dynamics and specifications and long-standing customer relationships. Our inability to retain, develop or hire qualified employees would restrict our ability to grow our business, limit our ability to continue to successfully operate our business and result in lower operating results and profitability.

Our ability to compete effectively depends, in part, upon our ability to protect and preserve proprietary aspects of our intellectual property through a combination of patent, trademark, copyright and trade secret laws, as well as licensing agreements and third-party nondisclosure and assignment agreements. Because of the differences in foreign trademark, patent and other laws concerning proprietary rights, our intellectual property rights may not receive the same degree of protection in foreign countries as they would in the U.S. Our failure to obtain or maintain adequate protection of our intellectual property rights for any reason could have a material adverse effect on our business, results of operations and financial condition.

Our operations are subject to various federal, state, local and foreign environmental, health and safety laws and regulations. Violations of these laws and regulations, failure to obtain or maintain required environmental permits or non-compliance with any conditions contained in any environmental permit can result in substantial fines or penalties, injunctive relief, requirements to install pollution or other controls or equipment, civil and criminal sanctions, permit revocations and/or facility shutdowns. We could be held liable for the costs to address contamination of any real property we have ever owned, leased, operated or used, including as a disposal site. We could also incur fines, penalties, sanctions or be subject to third-party claims for property damage, personal injury or nuisance or otherwise as a result of violations of or liabilities under environmental laws in connection with releases of hazardous or other materials.

In addition, changes in, or new interpretations of, existing laws, regulations or enforcement policies, the discovery of previously unknown contamination, or the imposition of other environmental liabilities or obligations in the future, including additional investigation or other obligations with respect to any potential health hazards of our products or business activities or the imposition of new permit requirements, may lead to additional compliance or other costs that could have material adverse effect on our business, financial condition, results of operations and cash flows.

We will be required to devote significant management attention and resources to integrating the business practices and operations of NDS with our business. We may be unable to realize the planned synergies from the acquisition or other benefits in the timeframe that we expect or at all. We continue to assess synergies that we may realize as a combined company, the realization of which will depend on a number of factors.

The success of the acquisition, including anticipated synergies, benefits and cost savings, will depend, in part, on our ability to successfully combine and integrate our current operations with NDS’ business. If we experience difficulties with the integration process or other unforeseen costs, the anticipated benefits and cost savings of the acquisition may not be realized fully or at all or may take longer to realize than expected. The integration planning and implementation process will result in significant costs and divert management attention and resources. These integration matters could have an adverse effect on our combined company for an undetermined period after completion of the acquisition. In addition, the actual cost savings of the acquisition could be less than anticipated or otherwise offset by other factors.

Additional difficulties we may encounter as part of the integration process include the following:

•the costs of integration and compliance and the possibility that the full benefits anticipated to result from our acquisition of NDS will not be realized;

•any delay in the integration of management teams, strategies, operations, products and services;

•diversion of the attention of each company’s management as a result of our acquisition of NDS;

•differences in business backgrounds, corporate cultures and management philosophies that may delay successful integration;

•operating in foreign jurisdictions where we have no prior operating experience, including compliance, workforce and operational challenges;

•delays in the disposition of the NDS International Entities;

•the ability to retain key employees;

•the ability to create and enforce uniform standards, controls, procedures, policies and information systems;

•the challenge of integrating complex systems, technology, networks and other assets of NDS into those of ours in a seamless manner that minimizes any adverse impact on customers, suppliers, employees and other constituencies;

•potential unknown liabilities and unforeseen increased expenses or delays associated with the acquisition, including costs to integrate NDS beyond current estimates; or

•the disruption of, or the loss of momentum in, each company’s ongoing businesses or inconsistencies in standards, controls, procedures and policies.

Any of these factors could adversely affect each company’s ability to maintain relationships with customers, suppliers, employees and other constituencies or our ability to achieve the anticipated benefits of the acquisition or could reduce each company’s earnings or otherwise adversely affect our business and financial results after the acquisition. These risks are not limited to our acquisition of NDS and could also apply to our future acquisitions.

The acquisition of NDS could disrupt our and NDS’ businesses. We are dependent on the experience and industry knowledge of senior management and other key employees to execute our business plans, which could be disrupted by the unanticipated departure of any key member of our management team or employee base, as well as management or key employees of NDS. Our and NDS’ current and prospective employees may experience uncertainty about their roles within our company, which may have an adverse effect on the ability of each of us to attract or retain key management and other key personnel.

Accordingly, no assurance can be given that we will be able to attract or retain our and NDS’ key management personnel and other key employees to the same extent that our companies have previously been able to attract or retain such employees. In addition, because of the specialized and technical nature of our business, our future performance is dependent on the continued service of, and on our ability to attract and retain, qualified management, engineering, technical, marketing and support personnel.

Competition for such personnel is intense, and we may be unable to continue to attract or retain such personnel.

Following our acquisition of NDS, the size and complexity of our business will increase significantly beyond the current size of either our or NDS’ existing business. Our future success depends, in part, upon our ability to manage this expanded business, which will pose substantial challenges for management, including challenges related to the management and monitoring of new operations and new types of manufacturing processes and products and associated increased costs and complexity. There can be no assurances that we will be successful after completion of the acquisition or that we will realize the expected benefits currently anticipated from our acquisition of NDS.

Additionally, we may not be able to maintain the levels of revenue, earnings or operating efficiency that we and NDS have achieved or might achieve separately. The business and financial performance of NDS is subject to certain risks and uncertainties, including the risk of the loss of, or changes to, its relationships with its customers. We may be unable to achieve the same growth, revenues and profitability that NDS has achieved in the past.

Our indebtedness could have risks. For example, it could:

•make it more difficult for us to satisfy our obligations with respect to the Company’s existing debt obligations;

•increase our vulnerability to and compromise our flexibility to plan for, or react to, general adverse economic, industry or competitive conditions, including interest rate fluctuations, because a portion of our borrowings will be at variable rates of interest;

•cause us to be unable to meet the financial covenants contained in our debt agreements, or to generate cash sufficient to make required debt payments, which circumstances would have the potential of accelerating the maturity of some or all of our outstanding indebtedness;

•require us to dedicate a substantial portion of our cash flow from operations to payments on our indebtedness, thereby reducing the availability of our cash flow to fund working capital, capital expenditures, acquisitions, joint ventures and investments and other general corporate purposes, which could improve our competitive position, results of operations or share price;

•require us to sell debt or equity securities or to sell some of our core assets, possibly on unfavorable terms, to meet payment obligations;

•place us at a competitive disadvantage compared to our competitors that do not have the same level of indebtedness as we do and competitors that may be in a more favorable position to access additional capital resources;

•limit our ability to execute business development and acquisition activities to support our strategies;

•limit our ability to obtain additional indebtedness or equity due to applicable financial and restrictive covenants in our debt agreements; and

•limit our ability to refinance our indebtedness on more favorable terms.

We expect to pay principal and interest on current and future debt from cash provided by operating activities. Therefore, our ability to meet these payment obligations will depend on future financial performance and cash availability. If our cash flow and capital resources are insufficient to fund our debt obligations, we may be forced to reduce or delay expansion plans and capital expenditures, limit payment of dividends, sell material assets or operations, obtain additional capital or restructure our debt.

Sales of substantial amounts of our common stock in the public market, or the perception that these sales could occur, could cause the market price of our common stock to decline. Based on shares outstanding as of May 14, 2026, we have 76.6 million outstanding shares of common stock, including 0.2 million outstanding shares of our restricted stock, a significant portion of which are freely tradable without restriction under the Securities Act of 1933, as amended, (“Securities Act”) unless held by “affiliates,” as that term is defined in Rule 144 under the Securities Act. As of March 31, 2026, there were stock options outstanding to purchase a total of approximately 0.9 million shares of our common stock.

In addition, approximately 1.5 million shares of common stock are available for grant under our 2017 Omnibus Plan.

Certain of our significant stockholders may distribute shares that they hold to their investors who themselves may then sell into the public market. Such sales may not be subject to the volume, manner of sale, holding period and other limitations of Rule 144 of the Securities Act (“Rule 144”). As resale restrictions end, the market price of our common stock could decline if the holders of those shares sell them or are perceived by the market as intending to sell them.

In the future, we may issue additional shares of common stock or other equity or debt securities convertible into common stock in connection with a financing, acquisition, litigation settlement or employee arrangement or otherwise. Any of these issuances could result in substantial dilution to our existing stockholders and could cause the trading price of our common stock to decline.

As of May 14, 2026, our directors, officers and principal stockholders and their affiliates collectively own, or have the right to own within 60 days, approximately 16% of our outstanding shares of common stock. Additionally, our tax-qualified Retirement and Stock Ownership Plan (“KSOP”) holds shares of common stock that KSOP participants with ESOP accounts are entitled to vote on a one-for-one basis on any matter requiring the vote or consent of our stockholders. Thus, the collective voting power of our directors, officers and principal stockholders and their affiliates as of May 14, 2026 is approximately 22%, inclusive of the outstanding shares of common stock held by the KSOP. As a result, these stockholders, if they act together, may be able to control our management and affairs and most matters requiring stockholder approval, including the election of directors and approval of significant corporate transactions. This concentration of ownership may have the effect of delaying or preventing a change of control and might adversely affect the market price of our common stock. This concentration of ownership may not be in the best interests of our other stockholders.

The KSOP trustee has the ability to vote a significant block of shares on certain matters presented to stockholders for approval. Each participant with an ESOP account in the KSOP may direct the KSOP trustee on how to vote the shares of common stock allocated to the participant’s ESOP accounts in the KSOP; and the KSOP trustee may vote any shares of common stock for which no participant instructions were received in the same proportion as the allocated stock for which participants’ voting instructions have been received is voted.

Our amended and restated certificate of incorporation and amended and restated bylaws include a number of provisions that may discourage, delay or prevent a change in our management or control over us that stockholders may consider favorable. For example, our amended and restated certificate of incorporation and amended and restated bylaws, each as further amended, authorize the issuance of “blank check” preferred stock that could be issued by our board of directors to thwart a takeover attempt; provide that vacancies on our board of directors, including newly-created directorships, may be filled only by a majority vote of directors then in office; prohibit stockholders from calling special meetings of stockholders; prohibit stockholder action by written consent, thereby requiring all actions to be taken at a meeting of the stockholders; do not give the holders of our common stock cumulative voting rights with respect to the election of directors, which means that the holders of a majority of our outstanding shares of common stock can elect all directors standing for election; establish advance notice requirements for nominations for election to our board of directors or for proposing matters that can be acted upon by stockholders at stockholder meetings; require a super-majority stockholders vote of 75% to approve any reorganization, recapitalization, share exchange, share reclassification, consolidation, merger, conversion or sale of all or substantially all assets to which we are a party that is not approved by the affirmative vote of at least 75% of the members of our board of directors; and require the approval of holders of a majority of the outstanding shares of our voting common stock to amend the bylaws and at least 75% of the outstanding shares of our voting common stock to amend certain provisions of the certificate of incorporation.

Any provision of our amended and restated certificate of incorporation, amended and restated bylaws or Delaware General Corporation Law that has the effect of delaying or deterring a change in control could limit the opportunity for our stockholders to receive a premium for their shares of our common stock, and could also affect the price that some investors are willing to pay for our common stock.

Our amended and restated certificate of incorporation and amended and restated bylaws may also make it difficult for stockholders to replace or remove our management. These provisions may facilitate management entrenchment that may delay, deter, render more difficult or prevent a change in our control, which may not be in the best interests of our stockholders.

Our amended and restated certificate of incorporation provides that the Court of Chancery of the State of Delaware is the exclusive forum for: any derivative action or proceeding brought on our behalf; any action asserting a claim of breach of a fiduciary duty owed to us or our stockholders by our directors, officers, employees or agents; any action asserting a claim against us arising under the Delaware General Corporation Law, our amended and restated certificate of incorporation or our amended and restated bylaws; or any action asserting a claim against us that is governed by the internal affairs doctrine. Any person or entity purchasing or otherwise acquiring any interest in shares of our common stock shall be deemed to have notice of and to have consented to the provisions of our amended and restated certificate of incorporation described above. The choice of forum provision may limit a stockholder’s ability to bring a claim in a judicial forum that it finds favorable for disputes with us or our directors, officers, employees or agents, which may discourage such lawsuits against us or our directors, officers, employees or agents. If a court were to find the choice of forum provision contained in our amended and restated certificate of incorporation to be inapplicable or unenforceable in an action, we may incur additional costs associated with resolving such action in other jurisdictions, which could adversely affect our business and financial condition.

These risks include but are not limited to:

•taxation by multiple jurisdictions and the impact of such taxation on the effective tax rate and taxes paid;

•material liabilities under our self-insured programs for workers' compensation, automobile and product/general liability coverage as well as health coverage to our employees;

•fluctuations in our effective tax rate, including from the OBBBA signed July 4, 2025, Inflation Reduction Act of 2022, Tax Cuts and Jobs Act of 2017, the Coronavirus Aid, Relief, and Economic Security Act and any future tax legislation;

•the impact of tariffs;

•new or modified legislation related to health care;

•the review of potential weaknesses or deficiencies in the Company's disclosure controls and procedures, and discovering further weaknesses of which we are not currently aware, or which have not been detected;

•our inability to assure our stockholders that an active market for shares of our common stock can be sustained, and the market price of our common stock may be volatile and could decline in the future; and

•failure to meet the expectations of investors, including as a result of factors beyond our control.

None.

Our cybersecurity program is designed to assess, identify and manage material risks from cybersecurity threats, and is a component of our overall enterprise risk program. Our cybersecurity program is based on the National Institute of Standards and Technology Cybersecurity Framework, version 2.0. We conduct regular scans, penetration tests, and vulnerability assessments to identify potential threats or vulnerabilities in our systems. Our processes to assess, identify and manage material risks from cybersecurity threats include potential threats associated with third party service providers, including cloud-based platforms.

We believe we have invested in monitoring practices to reduce cybersecurity risks and continue to monitor our systems on an ongoing basis for compliance with applicable privacy regulations and any current or potential threats. We engage third-party service providers to enhance our risk prevention and mitigation efforts. We have periodically engaged third parties to serve in a consultative and advisory manner to review current and future strategies. We also purchase insurance to help protect us against the risk of cybersecurity breaches.

Board and Committee Oversight - Our Board of Directors has ultimate oversight of the Company’s cybersecurity programs and strategy, with the Audit Committee maintaining oversight responsibility in reviewing cybersecurity and other information technology risks. The Audit Committee assesses the steps management has taken to monitor, minimize or control such risks or exposures. The Company’s Chief Information Officer (“CIO”) presents a cybersecurity report to the Audit Committee each quarter. The report includes updates of recent cybersecurity threats, current key performance indicators of security controls and summaries of any recent incidents at the Company.

Management’s Role - The Company’s CIO, supported by the Director of IT Security and Compliance, manages cybersecurity risk. Our CIO has over 25 years of experience in information technology and eight years of experience with the Company. The Company’s enterprise-wide cybersecurity strategy is supported by policies, procedures, security controls and training designed to protect the Company’s IT systems, operations and sensitive data. Specifically, our Cyber Incident Response Plan provides a process by which our Company is informed about and monitors the prevention, detection, mitigation and remediation of cybersecurity incidents and includes engaging the Cybersecurity and Risk Management Committee (“CRMC”). The CRMC is a management committee established to identify, assess and manage material cybersecurity incidents, including the incident recovery process within the Company. Depending on the significance of the incident, the Cyber Incident Response Plan could include engaging affected internal and external parties, escalating the issue to executive management, notifying one or more members of our Audit Committee, maintaining communication with users and notifying law enforcement and government agencies as warranted.

For additional information regarding cybersecurity risks, see the risk factor captioned “Cybersecurity incidents may threaten our confidential information, disrupt operations and result in harm to our reputation and adversely impact our business and financial performance” under Part I, Item 1A “Risk Factors”.

Property - We have a network of 64 manufacturing plant locations and 41 distribution centers, summarized in the following table:

(1)Manufacturing plants and distribution centers in Mexico are owned or leased by our joint venture.

(2)Manufacturing plants and distribution centers owned or leased by our South America joint venture are not consolidated.

(3)The other facility is located in the Netherlands.

We currently own approximately 110,000 square feet in Hilliard, Ohio for our corporate headquarters through a joint venture and own our approximately 110,000 square foot ADS Engineering and Technology Center. Additionally, we lease an office space in Old Saybrook, Connecticut for our Infiltrator headquarters.

Our network of 64 manufacturing plants consists of 45 that are owned and 19 that are leased. We generally prefer to own our manufacturing plant locations, with a typical pipe manufacturing facility consisting of approximately 40,000 square feet and 15 to 20 acres of land for storage of pipe and related products. Our network of 41 distribution centers consists of 4 owned and 37 leased locations. We believe that our properties have been adequately maintained and are generally in good condition. The extent to which we use our properties varies by property, but we believe the capacity of our facilities is adequate for the level of production and distribution activities necessary in our business as presently conducted. Our Wastewater Segment utilizes 10 of our properties in the United States. The remainder of our properties are utilized by the Stormwater segment. Each distribution center carries pipe, fittings and other Allied Products per needs of the local market.

In-House Fleet - As of March 31, 2026, our in-house fleet consists of approximately 600 tractors and approximately 1,100 trailers that are specially designed to haul our lightweight pipe and fittings products.

The Company is involved from time to time in various legal proceedings that arise in the ordinary course of our business, including but not limited to commercial disputes, environmental matters, employee related claims, intellectual property disputes and litigation in connection with transactions including acquisitions and divestitures. The Company does not believe that such litigation, claims, and administrative proceedings will have a material adverse impact on our financial position or our results of operations. The Company records a liability when a loss is considered probable, and the amount can be reasonably estimated.

Market Information for Common Stock - Our common stock is listed and traded on the NYSE under the symbol “WMS”. During each quarter of fiscal 2026, 2025 and 2024, the Board of Directors approved a quarterly cash dividend of $0.18, $0.16 and $0.14 per share, respectively, to all common stockholders. During the first quarter of fiscal 2027, the Company declared a quarterly cash dividend of $0.20 per share of common stock. The dividend is payable on June 15, 2026 to stockholders of record at the close of business on June 1, 2026.

Holders of Record - As of May 14, 2026, we had 862 holders of record of our common stock. The number of holders of record is based upon the actual number of holders registered as of such date and does not include holders of shares in “street name” or persons, partnerships, associates, corporations or other entities in security position listings maintained by depositories.

Stock Performance Graph - The following graph presents a comparison from March 31, 2021 through March 31, 2026 of the cumulative return of our common stock, the Standard and Poor's Index and the Standard and Poor’s Mid Cap 400 - Capital Goods Index. The graph assumes investment of $100 on March 31, 2021 in our common stock and in each of the two indices and the reinvestment of dividends.

Recent Sales of Unregistered Securities - Since the completion of our IPO, we have not sold any securities without registration under the Securities Act of 1933, as amended.

Issuer Purchases of Equity Securities - In February 2026, we announced that our Board of Directors approved a new $1.0 billion stock repurchase authorization (the “Repurchase Program”) of ADS common stock in accordance with applicable securities laws. During fiscal 2026, we repurchased 0.7 million shares of common stock at a cost of $98.7 million. With the new authorization, the Repurchase Program has a total available capacity of $1.0 billion as of March 31, 2026. The Repurchase Program does not obligate us to acquire any particular amount of common stock and may be suspended or terminated at any time at our discretion.

The following table provides information with respect to repurchases of our common stock by us and our “affiliated purchasers” (as defined by Rule 10b-18(a)(3) under the Exchange Act) during the three months ended March 31, 2026.

Equity Compensation Plan Information - For equity compensation plan information, refer to “Part III, Item 12. Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters,” of this Annual Report on Form 10-K.

We are the leading manufacturer of innovative water management solutions in the stormwater and onsite wastewater industries, providing superior drainage solutions for use in the construction and agriculture marketplaces. Our innovative products, for which we hold many patents, are used across a broad range of end markets and applications, including non-residential, infrastructure and agriculture applications. We have established a leading position in many of these end markets by leveraging our national sales and distribution platform, industry-acclaimed engineering support, overall product breadth and scale plus manufacturing excellence.

Product Demand - There are numerous factors that influence demand for our products. Our businesses are cyclical in nature and sensitive to general economic conditions, primarily in the United States, Canada, Mexico and South America. The non-residential, residential, agricultural and infrastructure markets we serve are affected by the availability of credit, lending practices, interest rates and unemployment rates. Demand for new homes, farm income, commercial development and highway infrastructure spending have a direct impact on our financial condition and results of operations. Accordingly, the following factors may have a direct impact on our business in the markets in which our products are sold:

•the strength of the economy;

Growth in Allied Products - Our Allied Products include storm and onsite wastewater chambers, PVC drainage structures, fittings, stormwater filters and water separators. These products complement our pipe products and allow us to offer a comprehensive water management solution to our customers and drive organic growth. Our leading market position in pipe products allows us to cross-sell Allied Products effectively. Our comprehensive offering of Allied Products can also increase pipe sales in certain markets. Allied Products are less sensitive to resin prices since resin prices represent a smaller percentage of the cost for Allied Products. Our leading position in the pipe market has allowed us to increase organic growth of our Allied Products, and we also expect to expand our Allied Product offerings through acquisitions, including our recent acquisition of NDS.

Product Pricing - The price of our products is impacted by competitive pricing dynamics in our industry as well as by raw material costs. Our industry is highly competitive and the sales prices for our products may vary based on the sales policies of our competitors. Raw material costs represent a significant portion of the cost of goods sold for our products. We aim to increase our product selling prices in order to cover raw material price increases, including increases due to tariffs, but the inability to do so could impact our profitability. Movements in raw material, logistics or other overhead costs and resulting changes in the selling prices may also impact changes in period-to-period comparisons of net sales.

Material Conversion - Our HDPE and PP pipe, plastic leachfield chambers, onsite wastewater tanks and related water management product lines compete with other manufacturers of similar products as well as manufacturers of alternative products made with traditional materials, such as concrete, steel and PVC. Our net sales are driven by market trends, including the adoption of thermoplastic corrugated pipe products as a replacement for traditional materials. Thermoplastic corrugated pipe is generally lighter, more durable, more cost effective and easier to install than comparable products made from traditional materials.

We believe customers will continue to acknowledge the superior attributes and compelling value proposition of our thermoplastic products and expanded regulatory approvals allow for their use in new markets and geographies. In addition, we believe that PP pipe products will also help accelerate conversion given the additional applications for which our PP pipe products can be used.

Raw Material Costs - Our raw material cost and product selling prices fluctuate with changes in the price of resins utilized in production. We actively manage our resin purchases and pass fluctuations in the cost of resin through to our customers, where possible, in order to maintain our profitability. Fluctuations in the price of crude oil and natural gas prices may impact the cost of resin. In addition, changes in and disruptions to existing capacities could also significantly increase resin prices, often within a short period of time. Our ability to pass through raw material price increases to our customers may lag the increase in our costs of goods sold. Sharp rises in raw material prices over a short period of time have historically occurred with a significant supply disruption, which may increase prices to levels that cannot be fully passed through to customers due to pricing of competing products or the anticipated length of time the raw material pricing will stay elevated.

We currently purchase in excess of 1.0 billion pounds of virgin and recycled resin annually from approximately 450 suppliers in North America. As a high-volume buyer of resin, we are able to achieve economies of scale to negotiate favorable terms and pricing. Our purchasing strategies differ based on the material (virgin resin versus recycled material). The price movements of the different materials vary, resulting in the need to use a number of strategies to reduce volatility.

In order to reduce the volatility of raw material costs in the future, our raw material strategies for managing our costs include the following:

•increasing the use of low cost resin in place of virgin resin while meeting or exceeding industry standards;

•internally processing greater amounts of our recycled resin in order to closely monitor quality and minimize costs;

•managing a resin price risk program that may entail both physical fixed price and volume contracts; and

•maintaining supply agreements with our major resin suppliers that provide multi-year terms and volumes that are in excess of our projected consumption.

We also consume a large amount of energy and other petroleum products in our operations, including the electricity we use in our manufacturing process as well as the diesel fuel consumed in delivering a significant volume of products to our customers through our in-house fleet. As a result, our operating profit also depends upon our ability to manage the cost of the energy and fuel we require, as well as our ability to pass through increased prices or surcharges to our customers.

Seasonality - Our operating results are impacted by seasonality. Historically, sales of our products have been higher in the first and second quarters of each fiscal year due to favorable weather and longer daylight conditions accelerating construction project activity during these periods while fourth quarter results are impacted by the timing of spring in the northern United States and Canada. Seasonal variations in operating results may also be significantly impacted by inclement weather conditions, which can delay projects, resulting in decreased net sales for one or more quarters, but we believe that these delayed projects generally result in increased net sales during subsequent quarters.

In the non-residential, residential and infrastructure markets in the northern United States and Canada, the construction season typically begins to gain momentum in late March and lasts through November, before winter significantly slows the construction markets. In the southern and western United States, Mexico, Central America and South America, the construction markets are less seasonal. The agricultural drainage market is concentrated in the early spring just prior to planting and in the fall just after crops are harvested prior to freezing of the ground in winter.

Currency Exchange Rates - Although we sell and manufacture our products in many countries, our sales and production costs are primarily denominated in U.S. dollars. We have wholly-owned facilities in Canada, the Netherlands and joint venture facilities in Mexico, Chile, Brazil, Argentina, Colombia and Peru. The functional currencies in the areas in which we have wholly-owned facilities and joint venture facilities other than the U.S. dollar are the Canadian dollar, Euro, Mexican peso, Chilean peso, Brazilian real and Colombian peso. From time to time, we use derivatives to reduce our exposure to currency fluctuations.

•Net sales increased 5.0% to $3.1 billion

•Net income from continuing operations decreased 5.0% to $429.9 million

•Adjusted EBITDA increased 8.3% to $962.9 million

•Cash provided by operating activities increased $237.6 million to $819.1 million

•Free cash flow increased $200.7 million to $569.3 million

Net sales increased $146.1 million, or 5.0%, to $3,050.4 million, as compared to $2,904.2 million in the prior year. Stormwater sales increased $71.0 million, or 3.1%, to $2,397.4 million. Wastewater sales increased $75.1 million, or 13.0%, to $653.0 million.

Gross profit increased $73.1 million, or 6.7%, to $1,167.4 million as compared to $1,094.2 million in the prior year. The increase in gross profit is primarily driven by favorable volume, price/cost and mix of construction market and Infiltrator sales, partially offset by unfavorable fixed cost absorption as well as the mix impact from acquisitions.

Adjusted EBITDA, a non-GAAP financial measure, increased $73.7 million, or 8.3%, to $962.9 million, as compared to $889.2 million in the prior year. The increase is primarily due to the factors mentioned above. As a percentage of net sales, Adjusted EBITDA was 31.6% as compared to 30.6% in the prior year.

Following the acquisition of NDS, the Company realigned its reportable segments to align with the manner in which the CODM assesses performance and makes resource allocation decisions. The Company’s revised reportable segments consist of Stormwater and Wastewater (formerly referred to as the “Infiltrator” reportable segment). Further, the Company changed the measure used to evaluate segment profitability from adjusted gross profit to Adjusted EBITDA. Segment results for the historical periods presented in these consolidated financial statements have been recast to reflect these changes. The Segment Realignment had no impact on our previously reported consolidated net sales, income from operations, net income attributable to ADS or earnings per share.

We generate a greater portion of our net sales and Adjusted EBITDA in our Stormwater segment, which includes sales of high performance thermoplastic corrugated pipe and complementary products throughout the United States and certain international regions. We expect the percentage of total net sales and gross profit derived from the Wastewater segment to continue to increase in future periods as we continue to expand our wastewater management presence. See “Note 20. Business Segment Information” to our audited consolidated financial statements included in “Item 8. Financial Statements and Supplementary Data” of this Form 10-K.

Stormwater - The Stormwater segment manufactures and markets high performance thermoplastic corrugated pipe and complementary products designed as an integrated, end-to-end solution set which provides a comprehensive approach to managing stormwater from the moment it hits the ground until it is cleaned and returned to its natural environment. In February 2026, the Company acquired NDS to further expand the Stormwater product offering, enhance go-to-market capabilities in retail and distributor channels, and expand the Stormwater addressable market. Stormwater products are sold and manufactured throughout the United States and certain international regions, including Company owned facilities in Canada, subsidiaries that distribute to Europe and the Middle East, and exports through the Company’s joint ventures with local partners in Mexico and South America. The Company maintains and serves these markets through product distribution relationships with many of the largest waterworks distributors, buying groups and co-ops, major retailers as well as an extensive network of hundreds of small to medium-sized distributors. Our joint venture strategy has provided us with local and regional access to new international markets. The unconsolidated sales of the South American Joint Venture were $75.6 million, $72.3 million, and $75.9 million, in fiscal 2026, 2025, and 2024, respectively.

Wastewater - Wastewater (formerly “Infiltrator”) is a leading national provider of plastic leachfield chambers and systems, onsite wastewater tanks and accessories, primarily for use in residential applications. Wastewater products are used in onsite wastewater treatment systems in the United States and Canada.

The following table summarizes our operating results as a percentage of net sales that have been derived from our Consolidated Financial Statements for the fiscal years ended March 31, 2026 and 2025. We believe this presentation is useful to investors in comparing historical results.

Net sales - The following table presents net sales to external customers by reportable segment for the fiscal years ended March 31, 2026 and 2025.

Our consolidated net sales for the fiscal year ended March 31, 2026 increased by $146.1 million, or 5.0%, compared to fiscal 2025. The increase in Stormwater sales was primarily driven by NDS net sales of $48.8 million and an increase in demand for our Allied Products in the non-residential construction market. The increase in Wastewater sales was primarily driven by an increase of Orenco net sales of $52.6 million to account for a full year of sales in fiscal 2026 and an increase in demand in the construction market.

Cost of goods sold and Gross profit - The following table presents gross profit by reportable segment for the fiscal years ended March 31, 2026 and 2025.

Our consolidated Cost of goods sold for the fiscal year ended March 31, 2026 increased by $73.0 million or, 4.0%, and our consolidated Gross profit decreased by $73.1 million, or 6.7%, compared to the same period in fiscal 2025. The increase in gross profit for Stormwater is primarily due to favorable material costs and the acquisition of NDS. The increase in gross profit for Wastewater was driven by Orenco and volume.

Selling, general and administrative expenses - The following table presents Selling, general and administrative expenses as a percentage of sales for the fiscal years ended March 31, 2026 and 2025.

Selling, general and administrative expenses for the fiscal year ended March 31, 2026 increased $89.2 million from the same period in fiscal 2025. The increase in Selling, general and administrative expenses is primarily the result of an increase in transaction costs of $31.5 million due to the acquisition of NDS, incremental operating expenses of NDS and Orenco, unfavorable incentive and stock-based compensation, and realignment expenses of $12.0 million.

Loss on disposal of assets and costs from exit and disposal activities - The loss on disposal in fiscal 2026 was due to exit and disposal activities related to plant closures and asset disposals partially offset by the sale of properties held-for-sale. See “Note 3. Restructuring and Loss (Gain) on Disposal of Assets and Costs from Exit and Disposal Activities” for additional information.

Intangible amortization - Intangible amortization increased by $6.9 million primarily due to the increase in intangible assets due to the NDS acquisition and the accelerated method of amortization for customer relationships.

Interest expense - Interest expense increased $2.1 million for the fiscal year ended March 31, 2026 compared to the same period in fiscal 2025. The increase was primarily due to increased debt levels.

Interest income and other, net - Interest income and other, net increased by $10.6 million for the fiscal year ended March 31, 2026 compared to the same period in fiscal 2025. The increase was primarily due to increased cash balances in the fiscal year and unrealized gains related to derivatives.

See “Note 16. Income Taxes” for additional information.

Equity in net income of unconsolidated affiliates - The Equity in net income of unconsolidated affiliates increased for the fiscal year ended March 31, 2026 compared to the same period in fiscal 2025 due to the current period income at our South American Joint Venture.

Net income attributable to noncontrolling interest - Net income attributable to noncontrolling interest was relatively flat for fiscal year ended March 31, 2026 compared to the same period in fiscal 2025.

Net loss from discontinued operations - The loss from discontinued operations was attributable the NDS International entities classified as held for sale as of March 31, 2026.

The following table summarizes our operating results as a percentage of net sales that have been derived from our Consolidated Financial Statements for the fiscal years ended March 31, 2025 and 2024. We believe this presentation is useful to investors in comparing historical results.

Net sales - The following table presents net sales to external customers by reportable segment for the fiscal years ended March 31, 2025 and 2024.

Our consolidated net sales for the fiscal year ended March 31, 2025 increased by $29.8 million, or 1.0%, compared to fiscal 2024. The decrease in Net sales for Stormwater was primarily driven by unfavorable price/mix impact partially offset by higher demand in our Allied Products. The increase in Net sales for Wastewater was driven by improved price/mix and $46.4 million of net sales from Orenco.

Cost of goods sold and Gross profit - The following table presents gross profit by reportable segment for the fiscal years ended March 31, 2025 and 2024.

Our consolidated Cost of goods sold for the fiscal year ended March 31, 2025 increased by $81.5 million or, 4.7%, and our consolidated Gross profit decreased by $51.7 million, or 4.5%, compared to the same period in fiscal 2024. The decrease in gross profit for Stormwater is primarily due to unfavorable material cost and the decrease in Net sales in Pipe. The increase in gross profit for Wastewater was driven by improved pricing, improved material costs and the acquisition of Orenco.

Selling, general and administrative expenses - The following table presents Selling, general and administrative expenses as a percentage of sales for the fiscal years ended March 31, 2025 and 2024.

Selling, general and administrative expenses for the fiscal year ended March 31, 2025 increased $9.7 million from the same period in fiscal 2024. The increase in Selling, general and administrative expenses is primarily the result of the operating and acquisition expenses of Orenco partially offset by favorable incentive and stock-based compensation expense.

Loss (gain) on disposal of assets and costs from exit and disposal activities - The change in Loss (gain) on disposal of assets and costs from exit and disposal activities is primarily due to the closure of a plant and other asset disposals in fiscal 2025 compared to a gain on the sale of the assets of Spartan Concrete, Inc. in fiscal 2024, partially offset by the losses on the sale of the Paper Recycling business and disposal of other assets.

Intangible amortization - Intangible amortization increased by $1.1 million primarily due to the increase in intangible assets due to the Orenco acquisition.

Interest expense - Interest expense increased $2.9 million for the fiscal year ended March 31, 2025 compared to the same period in fiscal 2024. The increase was primarily due to an increase in interest rates.

Interest income and other, net - Interest income and other, net increased by $0.3 million for the fiscal year ended March 31, 2025 compared to the same period in fiscal 2024.

The change in the effective tax rate was primarily related to the increase of the income tax benefit related to the stock-based compensation windfall and the increase of income tax expense related to the executive compensation limitation in fiscal year 2025. See “Note 16. Income Taxes” for additional information.

Equity in net income of unconsolidated affiliates - The Equity in net income of unconsolidated affiliates decreased for the fiscal year ended March 31, 2025 compared to the same period in fiscal 2024 due to a decrease in the current period income at our South American Joint Venture.

Net income attributable to noncontrolling interest - Net income attributable to noncontrolling interest decreased for the fiscal year ended March 31, 2025 due to decreased net income at our ADS Mexicana joint venture.

EBITDA, Adjusted EBITDA and Adjusted EBITDA Margin - EBITDA, Adjusted EBITDA and Adjusted EBITDA Margin, non-GAAP financial measures, have been presented in this Annual Report on Form 10-K as supplemental measures of financial performance that are not required by, or presented in accordance with generally accepted accounting principles (“GAAP”) and should not be considered as alternatives to net income as measures of financial performance or any other performance measure derived in accordance with GAAP. We calculate Adjusted EBITDA as net income from continuing operations before interest, income taxes, depreciation and amortization, stock-based compensation expense, non-cash charges and certain other gains and expenses. We calculate Adjusted EBITDA Margin as Adjusted EBITDA divided by net sales.

EBITDA, Adjusted EBITDA and Adjusted EBITDA Margin are included in this Annual Report on Form 10-K because they are key metrics used by management and our Board of Directors to assess our financial performance. EBITDA, Adjusted EBITDA and Adjusted EBITDA Margin are frequently used by analysts, investors and other interested parties to evaluate companies in our industry. In addition to covenant compliance and executive performance evaluations, we use EBITDA, Adjusted EBITDA and Adjusted EBITDA Margin to supplement GAAP measures of performance to evaluate the effectiveness of our business strategies, to make budgeting decisions and to compare our performance against that of other peer companies using similar measures.

EBITDA, Adjusted EBITDA and Adjusted EBITDA Margin are not GAAP measures of our financial performance and should not be considered as alternatives to net income as measures of financial performance or any other performance measure derived in accordance with GAAP, and it should not be construed as an inference that our future results will be unaffected by unusual or non-recurring items. EBITDA, Adjusted EBITDA and Adjusted EBITDA Margin contain certain other limitations, including the failure to reflect our cash expenditures, cash requirements for working capital needs and cash costs to replace assets being depreciated and amortized. In evaluating EBITDA, Adjusted EBITDA and Adjusted EBITDA Margin, you should be aware that in the future we will incur expenses that are the same as or similar to some of the adjustments in this presentation, such as stock-based compensation expense, derivative fair value adjustments, and foreign currency transaction losses. Management compensates for these limitations by relying on our GAAP results in addition to using EBITDA, Adjusted EBITDA and Adjusted EBITDA Margin on a supplemental basis. Our measure of EBITDA, Adjusted EBITDA and Adjusted EBITDA Margin are not necessarily comparable to other similarly titled captions of other companies due to different methods of calculation.

(a)Includes costs associated with the optimization of the Company’s production, recycling and distribution network, as well as professional fees incurred in connection with supporting enterprise-wide restructuring and realignment initiatives. Excludes gain on sale of properties previously held-for-sale and equipment. See “Note 3. Restructuring and Loss (Gain) on Disposal of Assets and Costs from Exit and Disposal Activities” for additional information.

(b)Represents expenses recorded related to legal, accounting and other professional fees incurred in connection with business or asset acquisitions and dispositions.

(c)Includes derivative fair value adjustments, foreign currency transaction (gains) losses, legal settlements, inventory step-up costs, the proportionate share of interest, income taxes, depreciation and amortization related to the South American Joint Venture, which is accounted for under the equity method of accounting and executive retirement expense (benefit).

Historically we have funded our operations through internally generated cash flow supplemented by debt financings, equity issuance and finance and operating leases. These sources have been sufficient historically to fund our primary liquidity requirements, including working capital, capital expenditures, debt service and dividend payments. From time to time, we may explore additional financing methods and other means to raise capital. There can be no assurance that any additional financing will be available to us on acceptable terms or at all.

Free Cash Flow - Free cash flow is a non-GAAP financial measure that comprises cash flow from operations less capital expenditures. Free cash flow is a measure used by management and our Board of Directors to assess our ability to generate cash. Accordingly, free cash flow has been presented in this Annual Report on Form 10-K as a supplemental measure of liquidity that is not required by, or presented in accordance with GAAP, because management believes that free cash flow provides useful information to investors and others in understanding and evaluating our ability to generate cash flow from operations after capital expenditures. Free cash flow is not a GAAP measure of our liquidity and should not be considered as an alternative to cash flow from operating activities as a measure of liquidity or any other liquidity measure derived in accordance with GAAP.

Our measure of free cash flow is not necessarily comparable to other similarly titled captions of other companies due to different methods of calculation.

The following table presents key liquidity metrics utilized by management:

The following table summarizes our available liquidity under our Revolving Credit Facility as of March 31, 2026:

As of March 31, 2026, we had $25.7 million in cash that was held by our foreign subsidiaries, of which, $13.1 million was held by our Canadian subsidiaries. We continue to evaluate our strategy regarding foreign cash, but our earnings in foreign subsidiaries still remain indefinitely reinvested, except for Canada. See “Note 16. Income Taxes” for additional discussion of our plans to repatriate earnings from Canada.

In fiscal 2026, our cash balance decreased by $235.3 million. Cash outflows from the acquisition of NDS, repayment of the term loan and Senior Notes due 2027, and capital expenditures of $249.8 million were partially offset by cash generated from operations, issuance of the Senior Notes due 2034, proceeds from the new term loan facility, changes in working capital and dispositions of assets. Our decrease of cash in fiscal 2025 was $26.6 million. Cash generated from operations, changes in working capital and dispositions of assets was offset by the acquisition of Orenco, capital expenditures of $212.9 million, $69.9 million in share repurchases and $49.7 million of dividend payments.

As of March 31, 2026, we had $962.9 million in liquidity, including $223.0 million of cash and $739.9 million in borrowings available under our Revolving Credit Agreement, excluding $10.1 million of outstanding letters of credit. We believe that our cash on hand, together with the availability of borrowings under our Credit Agreement and other financing arrangements and cash generated from operations, will be sufficient to meet our working capital requirements, anticipated capital expenditures, and scheduled principal and interest payments on our indebtedness for at least the next twelve months.

Working Capital - Working capital is an indication of liquidity and potential need for short-term funding. We define working capital as current assets less current liabilities. Working capital decreased to $721.4 million as of March 31, 2026, from $926.4 million as of March 31, 2025, primarily due to a decrease in cash due to the acquisition of NDS and capital expenditures, partially offset by cash flow from operations and the incremental working capital of NDS.

Operating Cash Flows - During fiscal 2026, 2025 and 2024, cash provided by operating activities was $819.1 million, $581.5 million and $717.9 million, respectively. Cash flow from operating activities for all periods was primarily driven by operating income and changes in working capital.

Investing Cash Flows - During fiscal 2026, cash used for investing activities was $1,211.8 million. The cash used for investing cash flows was primarily for the acquisition of NDS and capital expenditures. Capital expenditures increased in fiscal 2026 compared to fiscal 2025.

Our capital expenditures in fiscal 2026 were used primarily to support facility expansions, equipment replacements, technology improvement initiatives and our corporate headquarters.

During fiscal 2025, cash used for investing activities was $447.9 million. The cash used for investing cash flows was primarily from the acquisition of Orenco and capital expenditures. Capital expenditures increased in fiscal 2025 compared to fiscal 2024. Our capital expenditures in fiscal 2025 were used primarily to support new facilities, facility expansions to increase production capacity and recycling capabilities, manufacturing equipment replacements and upgrades, and technology initiatives to improve customer service.

During fiscal 2024, cash used for investing activities was $155.7 million. The cash used for investing cash flows was primarily from capital expenditures offset with the disposition of assets or businesses. Our capital expenditures in fiscal 2024 were used primarily to support new facilities, facility expansions, equipment replacements and technology improvement initiatives.

We currently anticipate that we will make capital expenditures of approximately $200 million in fiscal 2027 to focus on growth and productivity through increasing our manufacturing capacity and investing in automation. Such capital expenditures are expected to be financed using funds generated by operations. We had approximately $100 million of open orders through purchase commitments as of March 31, 2026.

Financing Cash Flows - During fiscal 2026, cash provided by financing activities was $156.3 million. During fiscal 2026, we received proceeds from the Term Loan Facility (as defined below) and issued 2034 Notes (as defined below) of $600.0 million and $500.0 million, respectively, we repaid the Initial Term Loan Facility (as defined below) and the 2027 Notes (as defined below) of $413.3 million and $350.0 million, respectively. Additionally, we repurchased shares at a cost of $92.0 million and made dividend payments of $56.1 million.

During fiscal 2025, cash used in financing activities was $157.7 million. During fiscal 2025, we repurchased shares at a cost of $69.9 million and made dividend payments of $49.7 million.

During fiscal 2024, cash used in financing activities was $284.3 million. During fiscal 2024, we repurchased shares at a cost of $207.3 million and made dividend payments of $47.7 million.

See “Note 7. Leases” and “Note 13. Debt” to our consolidated financial statements included in “Item 8. Financial Statements and Supplementary Data” for a discussion of the Company’s financing transactions, including the Secured Bank Loans, the Senior Notes and the Company’s finance lease obligations.

Senior Secured Credit Facility - On July 31, 2019, we entered into a credit agreement (the “Base Credit Agreement”) by and among, the Company, as borrower, Barclays Bank PLC, as administrative agent, and several lenders from time to time party thereto. Among other things, the Base Credit Agreement provided for a term loan facility in the initial aggregate principal amount of $1.3 billion (the “Initial Term Loan Facility”) and a revolving credit facility in an initial aggregate amount of up to $350 million (the “Initial Revolving Credit Facility”), which included a sub-limit for a letter of credit sub-facility in the initial aggregate amount of up to $50 million.

On September 24, 2019, we entered into a First Amendment (the “First Amendment”) to the Company’s Base Credit Agreement subsequent to the common stock offering and Senior Notes due in 2027.

On May 26, 2022, the Company entered into a Second Amendment (the “Second Amendment”) to the Company's Base Credit Agreement with, among others, Barclays Bank PLC, as administrative agent under the Initial Term Loan Facility, and PNC Bank, National Association, as new administrative agent under the Initial Revolving Credit Facility. Among other things, the Second Amendment (i) amended the Base Credit Agreement by increasing the Initial Revolving Credit Facility (the “Second Amended Revolving Credit Facility”) from $350.0 million to $600.0 million (including an increase of the sub-limit for the swing-line sub-facility from $50.0 million to $60.0 million) and extended the maturity date of the Revolving Credit Facility to the earlier of May 26, 2027 or the date that is six months prior to the earliest maturity date of the outstanding loans under the Initial Term Loan Facility.

On November 26, 2025, the Company entered into a Third Amendment (the “Third Amendment”) to the Company’s Base Credit Agreement. Among other things, the Third Amendment modified the termination date of the Second Amended Revolving Credit Facility to remove reference to the earliest maturity date of the loans outstanding under the Initial Term Loan Facility.

On February 27, 2026, the Company entered into a Fourth Amendment (the “Fourth Amendment”) to the Company’s Base Credit Agreement (the Base Credit Agreement as amended by the First Amendment, the Second Amendment, the Third Amendment and the Fourth Amendment, the “Credit Agreement”) with, among others, certain subsidiaries of the Company, as guarantors, Bank of America, N.A., as administrative agent under the Term Loan Facility (as defined below) and PNC Bank, National Association, as administrative agent under the Revolving Credit Facility (as defined below) and as successor administrative agent, Barclays Bank PLC, as predecessor administrative agent, and the several financial institutions from time to time party thereto as lenders. Among other things, the Fourth Amendment (i) increased the Amended Revolving Credit Facility from $600 million to $750 million (the “Revolving Credit Facility”), including an increase of the sub-limit for the letter of credit sub-facility from $60 million to $75 million, (ii) refinanced the outstanding amounts owing under the Initial Term Loan Facility by providing for a new term loan facility in the initial aggregate principal amount of $600 million (the “Term Loan Facility”), (iii) extended the maturity date of the Revolving Credit Facility to February 27, 2031, (iv) extended the maturity date of the Term Credit Facility to February 28, 2033, (v) revised the “applicable margin” to provide for a range of 125 basis points to 225 basis points (for Term Benchmark based loans) and 25 basis points to 125 basis points (for base rate loans), as determined based on the consolidated senior secured net leverage ratio ranging from less than 1.50 to 1.00 to greater than or equal to 3.50 to 1.00, (vi) provides for incremental facilities in the aggregate maximum amount of the greater of $350 million or 100% of consolidated EBITDA for the most recently ended four consecutive fiscal quarters, and (vii) amended certain covenant baskets under the Credit Agreement to align with the growth of the Company.

At the option of the Company, borrowings under the Term Loan Facility and under the Revolving Credit Facility (subject to certain limitations) bear interest at either a base rate (as determined pursuant to the Fourth Amendment) or at a Term Benchmark rate (as defined in the Fourth Amendment), plus the applicable margin as set forth therein from time to time. In the case of the Revolving Credit Facility, the applicable margin is based on the Company's consolidated senior secured net leverage ratio (as defined in the Fourth Amendment). All borrowings under the Term Loan Facility as described above initially bear interest at the Term Benchmark rate (as defined in the Fourth Amendment). In the case of the Term Loan Facility, the applicable margin shall be, for loans bearing interest at the Term Benchmark rate, 1.625%, and for loans bearing interest at the base rate, 0.625%.

Issuance of Senior Notes due 2027 - On September 23, 2019, we issued $350.0 million aggregate principal amount of senior notes (“2027 Notes”), pursuant to the Indenture dated September 23, 2019 (the “2027 Indenture”), among the Company, the guarantors party thereto (the “Guarantors”) and U.S. Bank Trust Company, National Association (formerly known as U.S. Bank National Association), as Trustee (the “Trustee”). The 2027 Notes were offered and sold either to persons reasonably believed to be “qualified institutional buyers” pursuant to Rule 144A under the Securities Act or to persons outside the United States under Regulation S of the Securities Act. We may redeem the 2027 Notes, in whole or in part, at any time on or after September 30, 2022 at established redemption prices set forth in the 2027 Indenture. On February 27, 2026, we redeemed all of our outstanding 2027 Notes in the original aggregate principal amount of $350.0 million at a redemption price equal to 100% of the principal amount plus accrued and unpaid interest, to, but excluding, the redemption date in connection with our issuance of $500.0 million aggregate principal amount of 5.375% senior notes due 2034 (the “2034 Notes”). See “Note 13. Debt” for further information on the 2027 Notes and 2034 Notes.

Equipment Financing - In November 2021, we purchased material handling equipment, trucks and trailers previously leased under a master lease agreement and classified as finance leases. The purchase was funded with debt through the Master Lease Agreement and Interim Funding Schedule with Fifth Third. The assets acquired are titled to the Company and included in Property, plant and equipment, net on our Consolidated Balance Sheet. The equipment financing has a balance of $3.1 million and had an initial term of between 12 and 84 months, based on the life of the equipment. The equipment financing bears a weighted average interest of 1.8% as of March 31, 2026.

Issuance of Senior Notes Due 2030 - On June 9, 2022, we issued $500.0 million aggregate principal amount of 6.375% its senior notes (the “2030 Notes”) pursuant to an Indenture, dated June 9, 2022 (the “2030 Indenture”), among the Company, the Guarantors and the Trustee.

The 2030 Notes were offered and sold either to persons reasonably believed to be “qualified institutional buyers” pursuant to the Securities Act or to persons outside the United States under Regulation S of the Securities Act. See “Note 13. Debt” for further information on the 2030 Notes.

Issuance of Senior Notes Due 2034 - On February 27, 2026, we issued $500.0 million aggregate principal amount of 5.375% senior notes due 2034 pursuant to an Indenture, dated February 27, 2026 (the “2034 Indenture”), among the Company, the Guarantors and the Trustee. The 2034 Notes were offered and sold either to persons reasonably believed to be “qualified institutional buyers” pursuant to the Securities Act or to persons outside the United States under Regulation S of the Securities Act. See “Note 13. Debt” for further information on the 2034 Notes.

The Credit Agreement requires, if, on the last day of each fiscal quarter, the aggregate amount of outstanding exposure under the Revolving Credit Facility exceeds 35% of the aggregate maximum amount of commitments under the Revolving Credit Facility then in effect, the Company is to maintain a consolidated senior secured net leverage ratio not to exceed 4.25 to 1.00 for any four consecutive fiscal quarter periods.

The Credit Agreement also includes other covenants, including negative covenants that, subject to certain exceptions, limit the Company's and its restricted subsidiaries’ (as defined in the Credit Agreement) ability to, among other things: (i) incur additional debt, including guarantees; (ii) create liens upon any of their property; (iii) enter into any merger, consolidation or amalgamation, liquidate, wind up or dissolve, or dispose of all or substantially all of their property or business; (iv) dispose of assets; (v) pay subordinated debt; (vi) make certain investments; (vii) enter into swap agreements; (viii) engage in transactions with affiliates; (ix) engage in new lines of business; (x) modify certain material contractual obligations, organizational documents, accounting policies or fiscal year; or (xi) create or permit restrictions on the ability of any subsidiary of any Loan Party (as defined in the Credit Agreement) to pay dividends or make distributions to the Company or any of its subsidiaries.

The Credit Agreement also contains customary provisions requiring the following mandatory prepayments (subject to certain exceptions and limitations): (i) annual prepayments (beginning with the fiscal year ending March 31, 2027) with a percentage of excess cash flow (as defined in the Credit Agreement); (ii) 100% of the net cash proceeds from any non-ordinary course sale of assets and certain casualty or condemnation events; and (iii) 100% of the net cash proceeds of indebtedness not permitted to be incurred under the Credit Agreement. For further information, see “Note 13. Debt” to the Consolidated Financial Statements. We were in compliance with our debt covenants as of March 31, 2026.

We do not have any off-balance sheet arrangements, with the exception of the guarantee of 50% of certain debt of our unconsolidated South American Joint Venture, as further discussed in “Note 12. Related Party Transactions” of our Consolidated Financial Statements included in “Item 8. Financial Statements and Supplementary Data,” of this Form 10-K. Our maximum potential obligation under this guarantee totals $5.5 million as of March 31, 2026. The maximum borrowing permitted under the South American Joint Venture’s credit agreement is $11.0 million. As of March 31, 2026, our South American Joint Venture had no outstanding debt subject to our guarantee. We do not believe that this guarantee will have a current or future effect on our financial condition, results of operations, liquidity, or capital resources.

Our discussion and analysis of financial condition and results of operations are based on our consolidated financial statements, which have been prepared in accordance with GAAP. The preparation of the consolidated financial statements requires management to make estimates and judgments that affect the reported amounts in our consolidated financial statements and accompanying notes. Certain of our accounting policies involve a higher degree of judgment and complexity in their application, and therefore, represent the critical accounting policies used in the preparation of our financial statements. If different assumptions or conditions were to prevail, the results could be materially different from our reported results. We believe the following accounting policies may involve a higher degree of judgment and complexity in their application and represent the critical accounting policies used in the preparation of our financial statements. For additional discussion of our significant accounting policies, see “Note 1. Background and Summary of Significant Accounting Policies” to our consolidated financial statements included in “Item 8. Financial Statements and Supplementary Data” included in this Form 10-K.

For a discussion of recent accounting pronouncements, see “Note 1. Background and Summary of Significant Accounting Policies” to our consolidated financial statements included in “Item 8. Financial Statements and Supplementary Data.”

We are subject to various market risks, primarily related to changes in interest rates, credit risk, raw material supply prices, and, to a lesser extent, foreign currency exchange rates. Our financial position, results of operations or cash flows may be negatively impacted in the event of adverse movements in the respective market rates or prices in each of these risk categories. Our exposure in each category is limited to those risks that arise in the normal course of business.

Interest Rate Risk - We are subject to interest rate risk associated with our debt. Changes in interest rates impact the fair value of our fixed-rate debt, but there is no impact to earnings and cash flow. Alternatively, changes in interest rates do not affect the fair value of our variable-rate debt, but they do affect future earnings and cash flow. The Revolving Credit Facility and Term Note bear interest at variable rates, either SOFR or the Prime Rate, at our option, plus applicable pricing margins. A 1.0% increase in interest rates on our variable-rate debt would increase our annual forecasted interest expense by approximately $6.0 million based on our borrowings as of March 31, 2026. Assuming the Revolving Credit Facility is fully drawn, each 1.0% increase or decrease in the applicable interest rate would change our interest expense by approximately $13.5 million, for the year ended March 31, 2026.

Credit Risk - Financial instruments that potentially subject us to a concentration of credit risk consist principally of accounts receivable. We provide our products to customers based on an evaluation of the customers’ financial condition, generally without requiring collateral. Exposure to losses on receivables is principally dependent on each customer’s financial condition. We monitor the exposure for credit losses and maintain allowances for anticipated losses. Concentrations of credit risk with respect to our accounts receivable are limited due to the large number of customers comprising our customer base and their dispersion among many different geographies and end markets.

Raw Material and Commodity Price Risk - Our primary raw materials used in the production of our products are HDPE and PP resins. As these resins are hydrocarbon-based materials, changes in the price of feedstocks, such as crude oil derivatives and natural gas liquids, as well as changes in the market supply and demand may cause the cost of these resins to fluctuate significantly.

We have supply agreements with our major resin suppliers that provide multi-year terms and volumes that are in excess of our projected consumption. These supply agreements generally do not contain fixed prices, exposing us to pricing risk. Given the significance of these costs and the inherent volatility in supplier pricing, our ability to reflect these changes in the cost of resins in our product selling prices in an efficient manner contributes to the management of our overall risk and the potential impact on our results of operations. A 1% increase in the price of resin would increase our cost of goods sold by approximately $4.3 million.

Inflation Risk - Our cost of goods sold is subject to inflationary pressures and price fluctuations of the raw materials we use, primarily HDPE and PP resins. Historically, we have generally been able, over time, to recover the effects of inflation and price fluctuations through sales price increases and production efficiencies related to technological enhancements and improvements. However, we cannot reasonably estimate our ability to successfully recover any price increases.

Foreign Currency Exchange Rate Risk - We have operations outside of the United States, which primarily use the respective local currency as their functional currency. Each of these operations may enter into contractual arrangements with customers or vendors that are denominated in currencies other than its respective functional currency. Consequently, our results of operations may be affected by exposure to changes in foreign currency exchange rates and economic conditions in the regions in which we sell or distribute our products. Exposure to variability in foreign currency exchange rates from these transactions is managed, to the extent possible, by natural hedges which result from purchases and sales occurring in the same foreign currency within a similar period of time, thereby potentially offsetting each other.

In addition to the foreign currency transaction-related gains and losses that are reflected within the results of operations, we are subject to foreign currency translation risk, as the financial statements for our foreign subsidiaries are measured and recorded in the respective subsidiary’s functional currency and translated into U.S. dollars for financial reporting purposes.

The Report of Independent Registered Public Accounting Firm, Consolidated Financial Statements and supplementary financial data required for this Item are set forth on pages F-1 through F-36 of this Annual Report on Form 10-K and are incorporated herein by reference. Our independent registered public accounting firm is Deloitte & Touche LLP, Columbus, Ohio, Public Company Accounting Oversight Board ID Number: 34.

None.

Under the supervision and with the participation of our management, including our Chief Executive Officer and our Chief Financial Officer, we evaluated the effectiveness of our disclosure controls and procedures as defined in Exchange Act Rules 13a-15(e) and 15d-15(e), as of March 31, 2026. Disclosure controls and procedures are designed to ensure that information required to be disclosed in our reports filed or submitted under the Exchange Act are recorded, processed, summarized and reported, within the time periods specified under Securities Exchange Commission (“SEC”) rules and forms. Management recognizes that any controls and procedures, no matter how well designed and operated, can provide only reasonable assurance of achieving their objectives, and management necessarily applies its judgment in evaluating the cost-benefit relationship of possible controls and procedures.

Based on the evaluation of our disclosure controls and procedures, our Chief Executive Officer and Chief Financial Officer concluded that our disclosure controls and procedures were effective as of March 31, 2026.

Management is responsible for establishing and maintaining adequate internal control over financial reporting, as such term is defined in Exchange Act Rules 13a-15(f) and 15d-15(f). Because of its inherent limitations, internal control over financial reporting may not prevent or detect all misstatements. Also, projections of any evaluation of effectiveness to future periods are subject to the risk that controls may become inadequate because of changes in conditions, or that the degree of compliance with policies or procedures may deteriorate.

Management, including our Chief Executive Officer and our Chief Financial Officer, assessed the effectiveness of our internal control over financial reporting as of March 31, 2026. In making this assessment, management used the criteria set forth by the Committee of Sponsoring Organizations of the Treadway Commission (“COSO”) in Internal Control — Integrated Framework (2013).

A material weakness in internal controls is a deficiency, or a combination of deficiencies, in internal control over financial reporting, such that there is a reasonable possibility that a material misstatement of our annual or interim financial statements will not be prevented or detected on a timely basis. Because of its inherent limitations, even appropriate internal control over financial reporting may not prevent or detect misstatements.

Based on this assessment, management has concluded that the Company’s internal control over financial reporting was effective as of March 31, 2026.

We have excluded from the scope of our assessment of internal control over financial reporting the operations and related assets of NDS which we acquired on February 2, 2026. This exclusion is in accordance with SEC guidance that an assessment of a recently acquired business's internal control over financial reporting may be omitted from management's report on internal control over financial reporting in the year of acquisition. At March 31, 2026 and for the period from acquisition through March 31, 2026, total assets, total revenues, and net income subject to NDS’ internal control over financial reporting represented 23%, 2%, and (1%) of consolidated total assets, net sales, and net income, respectively of ADS as of and for the year ended March 31, 2026.

Deloitte & Touche LLP, our independent registered public accounting firm, has issued an audit report on the effectiveness of our internal control over financial reporting as of March 31, 2026 and this report is included herein.

There were no changes in our internal control over financial reporting identified in management’s evaluation pursuant to Rules 13a15(d) or 15d-15(d) of the Exchange Act during the quarter ended March 31, 2026 that have materially affected, or are reasonably likely to materially affect, our internal control over financial reporting.

During the three months ended March 31, 2026, no director or officer of the Company adopted or terminated a “Rule 10b5-1 trading arrangement” or “non-Rule 10b5-1 trading arrangement,” as such terms are defined in Item 408(a) of Regulation S-K.

The information contained under the captions “CERTAIN INFORMATION REGARDING OUR EXECUTIVE OFFICERS,” “2026 NOMINEES FOR ELECTION TO THE BOARD OF DIRECTORS,” “DELINQUENT SECTION 16(A) REPORTS,” “CODES OF BUSINESS CONDUCT AND ETHICS,” “OTHER EXECUTIVE COMPENSATION POLICIES AND PRACTICES - Insider Trading Policy” and “COMMITTEES OF THE BOARD - AUDIT COMMITTEE” in our definitive Proxy Statement for the 2026 Annual Meeting of Shareholders, to be filed with the SEC pursuant to Regulation 14A promulgated under the Exchange Act (the “Proxy Statement”), is incorporated herein by reference.

The information contained under the captions “DIRECTOR COMPENSATION,” “COMPENSATION AND MANAGEMENT DEVELOPMENT COMMITTEE REPORT,” “COMPENSATION DISCUSSION AND ANALYSIS” and “COMPENSATION OUTCOMES FOR 2026” in the Proxy Statement is incorporated herein by reference. Notwithstanding the foregoing, the information contained in the Proxy Statement under the caption “COMPENSATION AND MANAGEMENT DEVELOPMENT COMMITTEE REPORT” shall be deemed furnished, and not filed, in this Report on Form 10-K and shall not be deemed incorporated by reference into any filing we make under the Securities Act of 1933, as amended, or the Exchange Act.

The information contained under the caption “SECURITY OWNERSHIP OF CERTAIN BENEFICIAL OWNERS AND MANAGEMENT” and “EQUITY COMPENSATION PLAN INFORMATION” in the Proxy Statement is incorporated herein by reference.

The information contained under the captions “CERTAIN RELATIONSHIPS AND RELATED-PARTY TRANSACTIONS” and “BOARD INDEPENDENCE” in the Proxy Statement is incorporated herein by reference.

The information contained under the caption “OTHER INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM INFORMATION - FEES” in the Proxy Statement is incorporated herein by reference.

1.Financial Statements. See “Table of Contents” on page 50.

2.Financial Statement Schedules. Schedule II - Consolidated Valuation and Qualifying Accounts.

Other schedules are omitted because they are not required or applicable, or the required information is included in our     consolidated financial statements or related notes.

3.Exhibits. See “Index to Exhibits.”

None.

Pursuant to the requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized.

Pursuant to the requirements of the Securities Exchange Act of 1934, this report has been signed below by the following persons in their indicated capacities, on May 21, 2026.

To the shareholders and the Board of Directors of Advanced Drainage Systems Inc.,

We have audited the accompanying consolidated balance sheets of Advanced Drainage Systems, Inc. and subsidiaries (the “Company”) as of March 31, 2026 and 2025, the related consolidated statements of operations, comprehensive income (loss), stockholder's equity and mezzanine equity and cash flows, for each of the three years in the period ended March 31, 2026, and the related notes and schedule listed in the Index at Item 15 (collectively referred to as the "financial statements"). In our opinion, the financial statements present fairly, in all material respects, the financial position of the Company as of March 31, 2026 and 2025, and the results of its operations and its cash flows for each of the three years in the period ended March 31, 2026, in conformity with accounting principles generally accepted in the United States of America.

We have also audited, in accordance with the standards of the Public Company Accounting Oversight Board (United States) (PCAOB), the Company's internal control over financial reporting as of March 31, 2026, based on criteria established in Internal Control — Integrated Framework (2013) issued by the Committee of Sponsoring Organizations of the Treadway Commission and our report dated May 21, 2026, expressed an unqualified opinion on the Company's internal control over financial reporting.

These financial statements are the responsibility of the Company's management. Our responsibility is to express an opinion on the Company's financial statements based on our audits. We are a public accounting firm registered with the PCAOB and are required to be independent with respect to the Company in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audits in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement, whether due to error or fraud. Our audits included performing procedures to assess the risks of material misstatement of the financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the financial statements. We believe that our audits provide a reasonable basis for our opinion.

The critical audit matter communicated below is a matter arising from the current-period audit of the financial statements that was communicated or required to be communicated to the audit committee and that (1) relates to accounts or disclosures that are material to the financial statements and (2) involved our especially challenging, subjective, or complex judgments. The communication of critical audit matters does not alter in any way our opinion on the financial statements, taken as a whole, and we are not, by communicating the critical audit matter below, providing a separate opinion on the critical audit matter or on the accounts or disclosures to which it relates.

Acquisition of NDS – Valuation of Customer Relationships Intangible Asset – Refer to Note 4 to the financial statements.

The Company completed the acquisition of the water management business of Norma Group SE, known as National Diversified Sales (“NDS”) on February 2, 2026. The preliminary fair value of consideration transferred was approximately $972.5 million, which represented the purchase price $984.9 million, net of cash acquired of $3.2 million and cash included in held for sale of $9.2 million. The Company accounted for the acquisition under the acquisition method of accounting for business combinations. Accordingly, the purchase price was allocated to the assets acquired and liabilities assumed based on their respective fair values, including customer relationships intangible asset of approximately $419.0 million. The fair value determination of the customer relationships intangible asset required management to make significant estimates and assumptions related to revenue growth rates and forecasts of future cash flows (together, the “forecasts”) and the selection of appropriate customer attrition and discount rates.

We identified the valuation of the customer relationships intangible asset as a critical audit matter because of the significant estimates and assumptions management used to estimate and record the fair value of the asset.

This required a high degree of auditor judgment and an increased extent of effort, including the need to involve our fair value specialists when performing audit procedures to evaluate the reasonableness of management’s forecasts and the selection of the customer attrition and discount rates.

Our audit procedures related to testing the assumptions identified above included the following, among others:

•We tested the effectiveness of controls over the valuation of the customer relationships intangible asset, including management’s controls over the forecasts, and the selection of the customer attrition and discount rates.

•We assessed the reasonableness of management’s forecasts by comparing the forecasted information to historical results and certain peer companies.

•We involved our fair value specialists to assist in evaluating the methodology used by management, ensuring it aligns with industry practices and standards.

•With the assistance of our fair value specialists, we evaluated the reasonableness of the following significant valuation assumptions:

◦Customer attrition rate by testing the source information underlying the determination of the rate and testing the mathematical accuracy of the calculation.

◦Discount rate by developing a range of independent estimates and comparing those to the discount rate selected by management.

We have served as the Company's auditor since 2002.

To the stockholders and the Board of Directors of Advanced Drainage Systems, Inc.,

We have audited the internal control over financial reporting of Advanced Drainage Systems, Inc. and subsidiaries (the “Company”) as of March 31, 2026, based on criteria established in Internal Control — Integrated Framework (2013) issued by the Committee of Sponsoring Organizations of the Treadway Commission (COSO). In our opinion, the Company maintained, in all material respects, effective internal control over financial reporting as of March 31, 2026, based on criteria established in Internal Control — Integrated Framework (2013) issued by COSO.

We have also audited, in accordance with the standards of the Public Company Accounting Oversight Board (United States) (PCAOB), the consolidated financial statements as of and for the year ended March 31, 2026, of the Company and our report dated May 21, 2026, expressed an unqualified opinion on those financial statements.

As described in Management's Report on Internal Control Over Financial Reporting, management excluded from its assessment the internal control over financial reporting at National Diversified Sales, which was acquired on February 2, 2026, and whose financial statements constitute 23%, 2%, and (1%) of consolidated total assets, net sales, and of net income, respectively, of the consolidated financial statement amounts as of and for the year ended March 31, 2026. Accordingly, our audit did not include the internal control over financial reporting at National Diversified Sales.

The Company's management is responsible for maintaining effective internal control over financial reporting and for its assessment of the effectiveness of internal control over financial reporting, included in the accompanying Management's Report on Internal Control Over Financial Reporting. Our responsibility is to express an opinion on the Company's internal control over financial reporting based on our audit. We are a public accounting firm registered with the PCAOB and are required to be independent with respect to the Company in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audit in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether effective internal control over financial reporting was maintained in all material respects. Our audit included obtaining an understanding of internal control over financial reporting, assessing the risk that a material weakness exists, testing and evaluating the design and operating effectiveness of internal control based on the assessed risk, and performing such other procedures as we considered necessary in the circumstances. We believe that our audit provides a reasonable basis for our opinion.

A company's internal control over financial reporting is a process designed to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles. A company's internal control over financial reporting includes those policies and procedures that (1) pertain to the maintenance of records that, in reasonable detail, accurately and fairly reflect the transactions and dispositions of the assets of the company; (2) provide reasonable assurance that transactions are recorded as necessary to permit preparation of financial statements in accordance with generally accepted accounting principles, and that receipts and expenditures of the company are being made only in accordance with authorizations of management and directors of the company; and (3) provide reasonable assurance regarding prevention or timely detection of unauthorized acquisition, use, or disposition of the company's assets that could have a material effect on the financial statements.

Because of its inherent limitations, internal control over financial reporting may not prevent or detect misstatements. Also, projections of any evaluation of effectiveness to future periods are subject to the risk that controls may become inadequate because of changes in conditions, or that the degree of compliance with the policies or procedures may deteriorate.