WOOD DALE, Ill., March 2, 2026 – Power Solutions International, Inc. (the “Company” or “PSI”) (Nasdaq: PSIX), a leader in the design, engineering and manufacture of emission-certified engines and power systems, announced fourth quarter and record full year 2025 financial results.

PSI reported net sales of $191.2 million and net income of $16.1 million, or $0.70 per diluted share, for the three months ended December 31, 2025. This compares to net sales of $144.3 million and net income of $23.3 million, or $1.01 per diluted share, for the same period in 2024, representing an increase of 33% in net sales and a decrease of 31% in net income.

Dino Xykis, Chief Executive Officer, said, “In 2025, the Company delivered record sales and profitability, with annual sales increasing 52% and annual net income rising 65%. This performance reflects continued demand for our power systems solutions, including demand within the data center market.

During the quarter, operating efficiency was impacted by the ramp up of new manufacturing capacity and increased volumes across certain product lines. Management has identified the key drivers and is executing specific actions to improve supply chain performance and manufacturing cost structures. We are beginning to see measurable improvements, which we expect to build and support margin expansion over time.

We recently completed the acquisition of MTL Manufacturing & Equipment, Inc. (“MTL”), a company that specializes in the welding and fabrication of steel components. This acquisition is expected to enhance PSI's competitive position in the data center market through vertical integration of MTL's specialized manufacturing capabilities. The integration is designed to provide improved supply chain control, reduced lead times, and access to MTL's established UL Solutions certifications.”

Sales for the fourth quarter of 2025 were $191.2 million, an increase of $46.9 million, or 33%, compared to the fourth quarter of 2024, primarily as a result of sales increases of $46.8 million and $3.0 million in the power systems and industrial end markets, respectively, partly offset by decreases of $2.9 million in the transportation end market. This shift in market mix reflects our deliberate strategic focus on higher-growth sectors such as data centers and oil and gas. In particular, we are prioritizing the rapidly expanding data center sector by enhancing our manufacturing capacity and capabilities to meet evolving customer demand.

Gross profit decreased by $1.4 million, or 3%, during the fourth quarter of 2025 as compared to the same period in the prior year. Gross margin in the fourth quarter of 2025 was 21.9%, a decrease of 8.0% compared to 29.9% in the same period last year. Gross margin was impacted by operating inefficiencies related to our accelerated production ramp-up for data center product lines.

Selling, general and administrative expenses of $12.8 million increased during the fourth quarter of 2025 by $0.4 million, or 3%, compared to the same period in the prior year. The variance reflects higher costs associated with employee incentive programs and increased sales and administrative expenses to support ongoing business growth in 2025.

Interest expense was $1.6 million in the fourth quarter of 2025 as compared to $2.4 million in the same period in the prior year, largely due to reduced outstanding debt and lower overall effective interest rates.

Income tax expense was $6.6 million in the fourth quarter of 2025, compared to an income tax benefit of $0.5 million in the same period of the prior year. For the full year, the Company recorded an income tax benefit of $10.6 million in 2025, compared to income tax expense of $0.9 million in 2024.

The 2025 tax benefit was primarily driven by a $38.3 million release of the valuation allowance, which contributed $1.66 to earnings per share. Beginning in 2026, the Company expects to return to a normalized effective income tax rate.

Net income and diluted earnings per share were $16.1 million and $0.70, respectively, in the fourth quarter of 2025, compared to $23.3 million and $1.01, respectively, for the fourth quarter of 2024. The decrease in net income for the fourth quarter was primarily driven by a higher effective tax rate in the current period compared to a tax benefit recognized in the prior year period, partially offset by higher sales volumes.

The Company’s cash and cash equivalents were approximately $41.3 million, while total debt was approximately $96.6 million at December 31, 2025. This compares to cash and cash equivalents of approximately $55.3 million and total debt of approximately $120.2 million at December 31, 2024.

Included in the Company’s total debt at December 31, 2025 were long-term borrowings of $95.0 million under the Revolving Credit Agreement.

Management remains confident in the Company’s long-term strategy and strong market positioning. We are making meaningful progress on our key operational initiatives and continue to strengthen our capabilities to support future growth. Management expects continued full year sales growth and moderate margin improvement from the products serving data center markets, offset by some headwinds from the oil and gas markets. As execution progresses and visibility improves, we look forward to providing more specific guidance.

Power Solutions International, Inc. (PSI) is a leader in the design, engineering and manufacture of a broad range of advanced, emission-certified engines and power systems. PSI provides integrated turnkey solutions to leading global original equipment manufacturers and end-user customers within the power systems, industrial and transportation end markets. The Company’s unique in-house design, prototyping, engineering and testing capabilities allow PSI to customize clean, high-performance engines using a fuel agnostic strategy to run on a wide variety of fuels, including natural gas, propane, gasoline, diesel and biofuels.

PSI develops and delivers complete power systems that are used worldwide in stationary and mobile power generation applications supporting standby, prime, demand response, and microgrid solutions, as well as products and packages supporting the rapidly growing data center markets. PSI’s industrial end market provides engine and battery powertrain solutions to serve applications such as forklifts, agricultural and turf, arbor care, industrial sweepers, aerial lifts, irrigation pumps, ground support, and construction equipment. PSI’s transportation end market provides engine powertrain solutions to specialized applications such as terminal tractors, port equipment, military vehicles, and other non-road vocational vehicles. For more information on PSI, visit www.psiengines.com.

This press release contains forward-looking statements regarding the current expectations of the Company about its prospects and opportunities. These forward-looking statements are entitled to the safe-harbor provisions of Section 21E of the Securities Exchange Act of 1934, as amended (the “Exchange Act”). These statements may involve risks and uncertainties. These statements often include words such as “anticipate,” “believe,” “budgeted,” “contemplate,” “estimate,” “expect,” “forecast,” “guidance,” “may,” “outlook,” “plan,” “projection,” “should,” “target,” “will,” “would” or similar expressions, but these words are not the exclusive means for identifying such statements. These statements are not guarantees of performance or results, and they involve risks, uncertainties and assumptions. Although the Company believes that these forward-looking statements are based on reasonable assumptions, there are many factors that could affect the Company’s results of operations and liquidity and could cause actual results, performance or achievements to differ materially from those expressed in, or implied by, the Company’s forward-looking statements.

The Company cautions that the risks, uncertainties and other factors that could cause its actual results to differ materially from those expressed in, or implied by, the forward-looking statements include, without limitation: the impact of the macro-economic environment in both the U.S.

and internationally on our business and expectations regarding growth of the industry; uncertainties arising from global events (including the Russia-Ukraine and Israel-Hamas conflicts), natural disasters or pandemics, and their impact on material prices; the Company’s ability to raise additional capital when needed and its liquidity; uncertainties around the Company’s ability to meet funding conditions under its financing arrangements and access to capital thereunder; the potential acceleration of the maturity at any time of the loans under the Company’s uncommitted revolving credit agreement through the exercise by any lender of its demand right in its Revolving Credit Agreement; the impact of rising interest rates; changes in economic conditions, including inflationary trends in the price of raw materials; our reliance on information technology and the associated risk involving potential security lapses and/or cyber-attacks; the ability of the Company to accurately forecast sales, and the extent to which sales result in recorded revenues; changes in customer demand for the Company’s products; volatility in oil and gas prices; the impact of U.S. tariffs on imports and exports; the impact of supply chain interruptions and raw material shortages, including compliance disruptions such as the UFLPA delaying goods from China; the potential impact of higher warranty costs and the Company’s ability to mitigate such costs; any delays and challenges in recruiting and retaining key employees consistent with the Company’s plans; the potential effects of damage to our reputation or other adverse consequences if our employees, suppliers, sub-suppliers or other contract parties, agents or business partners violate anti-bribery, competition, export and import, trade sanctions, data privacy, environmental, human rights or other laws; the impact of unanticipated changes in our effective tax rate, the adoption of new tax legislation or exposure to additional income tax liabilities; and the risks and uncertainties described in reports filed by the Company with the SEC, including without limitation its Annual Report on Form 10-K for the fiscal year ended December 31, 2025 and the Company’s subsequent filings with the SEC.

The Company’s forward-looking statements are presented as of the date hereof. Except as required by law, the Company expressly disclaims any intention or obligation to revise or update any forward-looking statements, whether as a result of new information, future events or otherwise.

Power Solutions International, Inc.

Kenneth Li

Chief Financial Officer

630-284-9719

kli@psiengines.com

Results of operations for the three months and year ended December 31, 2025, compared with the three months and year ended December 31, 2024 (UNAUDITED):

NM    Not meaningful

*    See reconciliation of non-GAAP financial measures to GAAP results below

In addition to the results provided in accordance with accounting principles generally accepted in the United States (“U.S. GAAP”) above, this press release also includes non-GAAP (adjusted) financial measures. Non-GAAP financial measures provide insight into selected financial information and should be evaluated in the context in which they are presented. These non-GAAP financial measures have limitations as analytical tools and should not be considered in isolation from, or as a substitute for, financial information presented in compliance with U.S. GAAP, and non-GAAP financial measures as reported by the Company may not be comparable to similarly titled measures reported by other companies. The non-GAAP financial measures should be considered in conjunction with the consolidated financial statements, including the related notes, and Management’s Discussion and Analysis of Financial Condition and Results of Operations included in the Company’s Form 10-K for the year ended December 31, 2025. Management does not use these non-GAAP financial measures for any purpose other than the reasons stated below.

The Company believes that Adjusted net income, Adjusted net income per share – diluted, EBITDA, and Adjusted EBITDA provide relevant and useful information, which is widely used by analysts, investors and competitors in its industry as well as by the Company’s management in assessing the performance of the Company. Adjusted net income is defined as net income as adjusted for certain items that the Company believes are not indicative of its ongoing operating performance. Adjusted net income per share – diluted is a measure of the Company’s diluted net earnings per share adjusted for the impact of special items. EBITDA provides the Company with an understanding of earnings before the impact of investing and financing charges and income taxes. Adjusted EBITDA further excludes the effects of other non-cash and certain other items that do not reflect the ordinary earnings of the Company’s operations.

Adjusted net income, Adjusted net income per share – diluted, EBITDA, and Adjusted EBITDA are used by management for various purposes, including as a measure of performance of the Company’s operations and as a basis for strategic planning and forecasting. Adjusted net income, Adjusted net income per share – diluted, and Adjusted EBITDA may be useful to an investor because these measures are widely used to evaluate companies’ operating performance without regard to items excluded from the calculation of such measures, which can vary substantially from company to company depending on the accounting methods, the book value of assets, the capital structure and the method by which the assets were acquired, among other factors. They are not, however, intended as an alternative measure of operating results or cash flow from operations as determined in accordance with U.S. GAAP.

1.Amounts reflect non-cash stock-based compensation expense for the year ended December 31, 2025 and 2024.

2.Amounts include severance expense for the year ended December 31, 2025 and 2024.

3.Amounts include legal settlements for the year ended December 31, 2025 and 2024.