Exhibit 99.1

GERDAU S.A.

Condensed consolidated interim financial statements

as of June 30, 2026

GERDAU S.A.

CONSOLIDATED BALANCE SHEETS

In thousands of Brazilian reais (R$)

(Unaudited)

The accompanying notes are an integral part of these Condensed Consolidated Interim Financial Statements

GERDAU S.A.

CONSOLIDATED BALANCE SHEETS

In thousands of Brazilian reais (R$)

(Unaudited)

The accompanying notes are an integral part of these Condensed Consolidated Interim Financial Statements

GERDAU S.A.

CONSOLIDATED STATEMENTS OF INCOME

In thousands of Brazilian reais (R$)

(Unaudited)

The accompanying notes are an integral part of these Condensed Consolidated Interim Financial Statements

GERDAU S.A.

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME

In thousands of Brazilian reais (R$)

(Unaudited)

The accompanying notes are an integral part of these Condensed Consolidated Interim Financial Statements      

GERDAU S.A.

CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY

in thousands of Brazilian reais (R$)

(Unaudited)

The accompanying notes are an integral part of these Condensed Consolidated Interim Financial Statements

GERDAU S.A.

CONSOLIDATED STATEMENTS OF CASH FLOWS

In thousands of Brazilian reais (R$)

(Unaudited)

The accompanying notes are an integral part of these Condensed Consolidated Interim Financial Statements

GERDAU S.A. 

NOTES TO THE CONDENSED CONSOLIDATED INTERIM FINANCIAL STATEMENTS 

as of June 30, 2026

(In thousands of Brazilian Reais – R$, unless otherwise stated) 

(Unaudited)

NOTE 1 - GENERAL INFORMATION

Gerdau S.A. is a publicly traded corporation (sociedade anônima) with its corporate domicile in the city of São Paulo, Brazil. Gerdau S.A and subsidiaries (collectively referred to as the “Company”) is a leading producer of long steel in the Americas and one of the largest suppliers of special steel in the world. In Brazil, the Company also produces flat steel and iron ore for its own consumption. The Company believes it is the largest recycler in Latin America and around the world it transforms each year millions of tons of scrap into steel, reinforcing its commitment to sustainable development of the regions where it operates. Gerdau is listed on the São Paulo and New York stock exchanges.

The Condensed Consolidated Interim Financial Statements of the Company were approved by the Management on August 4, 2026.

NOTE 2 - SUMMARY OF SIGNIFICANT ACCOUNTING PRACTICES

2.1 - Basis of Presentation

The Company’s Condensed Consolidated Interim Financial Statements for the three-month and six-month periods ended on June 30, 2026 have been prepared in accordance with International Accounting Standard (IAS) Nº 34, which establishes the content of condensed interim financial statements. These Condensed Consolidated Interim Financial Statements should be read in conjunction with the Consolidated Financial Statements of Gerdau S.A., as of December 31, 2025, which were prepared in accordance with International Financial Reporting Standards (IFRS) as issued by the International Accounting Standards Board - IASB.

The preparation of the Condensed Consolidated Interim Financial Statements in accordance with IAS 34 requires Management to make accounting estimates. The Condensed Consolidated Interim Financial Statements have been prepared using the historical cost as its basis, except for the valuation of certain financial instruments, which are measured at fair value.

The accounting policies applied in this Condensed Consolidated Interim Financial Statements are the same as those applied in the Consolidated Financial Statements for the year ended December 31, 2025.

2.2 – New accounting standards

The issued and/or reviewed IFRS standards made by the IASB that are effective for the year started in 2026 had no impact on the Company’s Financial Statements. In addition, the IASB issued/reviewed some IFRS standards, which have mandatory adoption for the year 2027 and/or after, and the Company is assessing the adoption impact of these standards in its Consolidated Financial Statements.

- Issuance of IFRS 18 – Presentation and Disclosure in Financial Statements. It will replace IAS 1 – Presentation of Financial Statements, introducing new requirements that will help achieve comparability of the financial performance of similar entities and provide more relevant information and transparency to users. Although IFRS 18 does not impact the recognition or measurement of items in financial statements, its impacts on presentation and disclosure are expected to be widespread, in particular those related to the demonstration of financial performance and the provision of performance measures defined by management within the financial statements. This standard is effective for years beginning on/or after January 1, 2027. The Company is evaluating the impacts on its Financial Statements of adopting this standard.

- Issuance and amendment of IFRS 19 – Subsidiaries without Public Accountability: Disclosures. This standard allows certain eligible subsidiaries of parent entities reporting under IFRS to apply reduced disclosure requirements. The standard is effective for annual reporting periods beginning on or after January 1, 2027. The Company does not expect material impacts on its Financial Statements, as this standard applies only to the financial statements of eligible subsidiaries.

- Amendment to IAS 21 – Translation to a Hyperinflationary Presentation Currency. Changes treatment and disclosure requirements originally set forth in this standard. This amendment is effective for fiscal years beginning on or after January 1, 2027. The Company does not expect significant impacts on its Financial Statements.

- Amendment to the Illustrative Examples of IFRS 7, IFRS 18, IAS 1, IAS 8, IAS 36 and IAS 37 – Disclosures about Uncertainties in the Financial Statements. Changes disclosure requirements originally set forth in these standards. This amendment is effective for fiscal years beginning on or after January 1, 2027. The Company does not expect significant impacts on its Financial Statements.

GERDAU S.A. 

NOTES TO THE CONDENSED CONSOLIDATED INTERIM FINANCIAL STATEMENTS 

as of June 30, 2026

(In thousands of Brazilian Reais – R$, unless otherwise stated) 

(Unaudited)

- Issuance of IFRS 20 – Regulatory Assets and Regulatory Liabilities. This new accounting standard establishes requirements for the recognition, measurement, presentation and disclosure of regulatory assets, regulatory liabilities, regulatory income and regulatory expenses arising from regulatory tariff arrangements. The standard aims to provide more relevant information about the effects of regulatory mechanisms on the financial position, financial performance and future cash flows of entities subject to rate regulation. This standard introduces specific criteria for the recognition of regulatory rights and obligations, as well as additional presentation and disclosure requirements in the financial statements. This standard is effective for fiscal years beginning on or after January 1, 2029. Early adoption of this standard is permitted; however, the Company has elected not to early adopt it. The Company is evaluating the impacts of adopting this standard on its financial statements.

- Amendment to IAS 28 – Investments in Associates and Joint Ventures. This amendment clarifies the eligibility criteria for applying the option to measure investments in associates and joint ventures at fair value through profit or loss in accordance with IFRS 9, aligning such requirements with the concepts introduced by IFRS 18. The amendment is applicable upon adoption of IFRS 18. The Company does not expect significant impacts on its Financial Statements arising from the adoption of this amendment.

NOTE 3 – CONDENSED CONSOLIDATED INTERIM FINANCIAL STATEMENTS

3.1 - Subsidiaries

The Company did not have material changes of interest in subsidiaries for the period ended on June 30, 2026, when compared to those existing on December 31, 2025.

3.2 - Joint Ventures

Listed below are the interests in joint ventures:

(*) The voting capital is substantially equal to the total capital. The interests reported represent the ownership percentage held directly and indirectly held in the joint venture.

Although the Company owns more than 50% of Gerdau Corsa S.A.P.I. de C.V., it does not consolidate the financial statements of this joint venture entity, due to joint control agreements with the other shareholders that prevent the Company from controlling the decisions in conducting the joint venture’s business. The Company owns 1.32% of MRS Logística S.A. and due to the existence of a shareholders’ agreement, a joint venture business and the existence of significant influence provided for in the accounting standard for the application of the equity method is characterized.

GERDAU S.A. 

NOTES TO THE CONDENSED CONSOLIDATED INTERIM FINANCIAL STATEMENTS 

as of June 30, 2026

(In thousands of Brazilian Reais – R$, unless otherwise stated) 

(Unaudited)

The Company presents the joint venture information in aggregate, since the investments in these entities are not individually material. The financial information of these joint ventures, accounted for under the equity method, is shown below:

3.3 — Associate companies

Listed below is the interest in associate companies:

(*) The voting capital is substantially equal to the total capital. The interests reported represent the ownership percentage held directly and indirectly.

As of June 30, 2026, the Company does not consolidate the Financial Statements of Dona Francisca Energética S.A. despite holding more than 50% of the total capital of this affiliate, due to protection rights granted to the other shareholders that prevent the Company from fully implementing decisions regarding the conduct of the affiliate’s business.

GERDAU S.A. 

NOTES TO THE CONDENSED CONSOLIDATED INTERIM FINANCIAL STATEMENTS 

as of June 30, 2026

(In thousands of Brazilian Reais – R$, unless otherwise stated) 

(Unaudited)

The summarized financial information of the associate companies, accounted for under the equity method, is shown as follows:

3.4 Acquisition of equity interest in companies

Dona Francisca Energética S.A. (DFESA)

On April 16, 2026 and June 15, 2026, the Company announced that it had submitted binding proposals to acquire the entire equity interests in Dona Francisca Energética S.A. (DFESA) held by Centrais Elétricas de Santa Catarina S.A. (CELESC) and Companhia Paranaense de Energia (COPEL), respectively. Each transaction corresponds to 23.03% of DFESA’s share capital and contemplates an enterprise value of R$150 million.

On July 20, 2026, the Company announced the completion of the acquisition of the entire equity interest in DFESA corresponding to 23.03% of its share capital held by CELESC. The transaction was completed after the fulfillment of the conditions precedent established for the operation, including approval by the Brazilian antitrust authority. The acquisition was completed at an enterprise value of R$150 million and, considering DFESA’s proportional consolidated cash position of approximately R$4 million, the Company made a total cash disbursement of approximately R$154 million, fully paid in cash using its own available resources.

The closing of the transaction with COPEL is, in turn, subject to the satisfaction of customary conditions precedent for this type of transaction, including approval by the Brazilian antitrust authority. The acquisition of the entire equity interest will result in the acquisition of control over DFESA, where the accounting impacts of the business combination are still being assessed.

The closing of the transaction with COPEL, in turn, remains subject to the fulfillment of customary conditions precedent for transactions of this nature, including approval by the Brazilian antitrust authority.

DFESA is a privately held corporation engaged in electric power generation through its 85% ownership interest in the consortium holding the concession for the Dona Francisca Hydroelectric Power Plant, located on the Jacuí River, in the State of Rio Grande do Sul, between the municipalities of Agudo and Nova Palma. The plant has an installed capacity of 125 MW and a firm energy output of 72.5 average MW, of which approximately 66 average MW are allocated to DFESA.

As of June 30, 2026, the Company held 53.94% of DFESA’s share capital, corresponding to 35.6 average MW of energy. Upon completion of the acquisitions of the equity interests held by CELESC and COPEL, following the fulfillment of the applicable conditions precedent and receipt of the required approvals, the Company will hold 100% of DFESA’s share capital through a total investment of R$300 million in enterprise value, plus the proportionate consolidated cash, increasing its self-production capacity by 30.4 average MW of energy. As a result, the Company will utilize the entire 65.94 average MW of firm energy available through DFESA for self-production purposes.

GERDAU S.A. 

NOTES TO THE CONDENSED CONSOLIDATED INTERIM FINANCIAL STATEMENTS 

as of June 30, 2026

(In thousands of Brazilian Reais – R$, unless otherwise stated) 

(Unaudited)

The acquisition is aligned with the Company’s capital allocation discipline, enhancing the cost competitiveness of its operations by increasing self-generation to more than 50% of its energy consumption, with a focus on renewable energy and in line with the decarbonization strategy previously disclosed by the Company.

NOTE 4 – CASH AND CASH EQUIVALENTS AND SHORT-TERM INVESTMENTS

Cash and cash equivalents

Immediately available investments include investments with maturity of up to 90 days or readily redeemable, that means, those that have immediate liquidity and low risk of fair value variation.

Short-term investments

Short-term investments include securities held for immediate trading or available for future sale and substantially include amounts in investment funds, whose portfolio is composed of Bank Deposit Certificates, government bonds, financial bills and debentures, among others, which are used to manage the cash from the Company’s operating activities and recorded at fair value. Income generated by these investments is recorded as financial income.

NOTE 5 – ACCOUNTS RECEIVABLE

GERDAU S.A. 

NOTES TO THE CONDENSED CONSOLIDATED INTERIM FINANCIAL STATEMENTS 

as of June 30, 2026

(In thousands of Brazilian Reais – R$, unless otherwise stated) 

(Unaudited)

Accounts receivable by aging are as follows:

NOTE 6 - INVENTORIES

The allowance for adjustment to net realizable value of inventories, on which the provision and reversal of provision are registered with impact on cost of sales, is as follows:

NOTE 7 – INCOME AND SOCIAL CONTRIBUTION TAXES

In Brazil, income taxes include federal income tax (IR) and social contribution (CS), which represents an additional federal income tax. The statutory rates for income tax and social contribution are 25% and 9%, respectively, and are applicable for the periods ended on June 30, 2026 and 2025. The foreign subsidiaries of the Company are subject to taxation at rates ranging between 23% and 35%, however, there are foreign subsidiaries—primarily engaged in financial activities—that are subject to tax rates as low as zero percent. The differences between the Brazilian tax rates and the rates of other countries are presented under “Difference in tax rates in foreign companies” in the reconciliation of income tax and social contribution below. The uncertain tax positions related to corporate income tax (IR) and social contribution (CS) are disclosed in Note 15.

GERDAU S.A. 

NOTES TO THE CONDENSED CONSOLIDATED INTERIM FINANCIAL STATEMENTS 

as of June 30, 2026 

(In thousands of Brazilian Reais – R$, unless otherwise stated) 

(Unaudited)

a) Reconciliations of income and social contribution taxes at statutory rates to amounts presented in the Statement of Income are as follows:

b) Tax assets not recognized:

Due to the lack of expectation to use tax losses, negative social contribution base and deferred exchange variation arising from some operations in Brazil, the Company did not recognize a portion of tax assets of R$ 1,133,089 (R$ 907,295 on December 31, 2025), which do not have an expiration date. The subsidiaries abroad had R$ 634,894 (R$ 701,413 as of December 31, 2025) of tax credits on capital losses for which deferred tax assets have not been recognized and which expire between 2027 and 2032 and also several Unrecognized tax loss carryforwards from state credits in the United States in the amount of R$ 235,313 (R$ 291,979 as of December 31, 2025), which expire at various dates between 2031 and 2038.

NOTE 8 – INVESTMENTS

NOTE 9 – PROPERTY, PLANT AND EQUIPMENT

a) Summary of changes in property, plant and equipment – during the three-month period ended on June 30, 2026, acquisitions amounted to R$ 1,008,294 (R$ 1,600,298 as of June 30, 2025), and disposals amounted to R$ 13,925 (R$ 17,478 as of June 30, 2025). During the six-month period ended on June 30, 2026, acquisitions amounted to R$ 2,105,959 (R$ 2,977,034 as of June 30, 2025), and disposals amounted to R$ 23,457 (R$ 30,872 as of June 30, 2025).

The additions to property, plant and equipment in the six-month period ended on June 30, 2026 include a non-cash effect amounted to R$ 126,279 (R$ 521,116 as of June 30, 2025).

b) Capitalized borrowing costs – borrowing costs capitalized during the three-month period ended on June 30, 2026 amounted to R$ 36,103 (R$ 58,187 as of June 30, 2025). Borrowing costs capitalized during the six-month period ended on June 30, 2026 amounted to R$ 81,274 (R$ 89,106 as of June 30, 2025).

c) Guarantees – no property, plant and equipment were pledged as collateral for loans and financing on June 30, 2026 and December 31, 2025.

GERDAU S.A. 

NOTES TO THE CONDENSED CONSOLIDATED INTERIM FINANCIAL STATEMENTS 

as of June 30, 2026 

(In thousands of Brazilian Reais – R$, unless otherwise stated) 

(Unaudited)

NOTE 10 – GOODWILL

The changes in goodwill are as follows:

The amounts of goodwill by segment are as follows:

As of June 30, 2026 and December 31, 2025, the goodwill balances of R$ 11,279,805 and R$ 11,995,727, respectively, are allocated to the North American segment.

NOTE 11 – TRADE ACCOUNTS PAYABLE (domestic market, debtor risk and imports)

Under “Trade Accounts Payable - Domestic Market”, the Company presents balances payable arising from the acquisition of goods and services in the domestic markets of each of the countries where the Company and its subsidiaries operate.

The Company has contracts with financial institutions in order to allow its suppliers to anticipate their receivables through an operation called “Trade Accounts Payable – Debtor Risk”. In this operation, suppliers can transfer, at their discretion, the right to receive the securities to a financial institution, which, in turn, becomes the holder of the rights of the suppliers’ receivables. The average discount rate on risk transactions carried out by our suppliers with financial institutions in Brazil and with subsidiaries in the United States was based on market conditions. The transfer of the right to receive the Company’s securities, at the supplier’s discretion, does not change the payment term, nor does it imply the payment of interest by the Company, as the financial cost of such transfer is the responsibility of the supplier. Therefore, the payment term for suppliers at risk drawn varies between 7 and 132 days, with the same payment term for suppliers who do not choose to advance their receivables through the operation called “Trade Accounts Payable – Debtor Risk”.

The amounts of liabilities under the supplier financing arrangement are considered to be reasonable approximations of their fair values, due to their short-term nature.

The balances presented as “Trade Accounts Payable - Imports” substantially refer to the purchase of coal and other raw materials abroad, where in commercial transactions the supplier may require the issuance of a letter of credit or similar risk mitigation instrument to ship the products. On June 30, 2026 and December 31, 2025, contracts negotiated via letter of credit had a payment term of up to 180 days and rates that also varied, depending on market conditions.

GERDAU S.A. 

NOTES TO THE CONDENSED CONSOLIDATED INTERIM FINANCIAL STATEMENTS 

as of June 30, 2026 

(In thousands of Brazilian Reais – R$, unless otherwise stated) 

(Unaudited)

The Company permanently monitors the composition of the portfolio and the conditions established with suppliers, which have not undergone significant changes in relation to what had been practiced historically.

NOTE 12 – LOANS AND FINANCING

Loans and financing are as follows:

As of June 30, 2026, the nominal weighted average cost of debts denominated in US dollars is 6.13% p.a. (6.12% p.a. on December 31, 2025), for debts denominated in Real of CDI -1.90% p.a. (CDI -2.11% p.a. on December 31, 2025) and for other currencies 3.34% p.a. (3.64% p.a. on December 31, 2025).

Loans and financing, denominated in Reais, are substantially indexed to the CDI (Interbank Deposit Certificates).

Summary of loans and financing by currency:

The amortization schedules of long-term loans and financing are as follows:

^(*) On June 30, 2026, the amounts represents dates from July 1, 2027 to December 31, 2027.

a) Credit Lines

In September 2022, the Company completed the renewal of the Global Credit Line in the total amount of US$ 875 million (equivalent to R$ 4,530 million as of June 30, 2026) with maturity in September 2027. The transaction aims to provide liquidity to operations in North America and Latin America, including Brazil. The companies Gerdau S.A., Gerdau Açominas S.A. and Gerdau Aços Longos S.A. provide guarantee for this transaction. As of June 30, 2026, no amount of this credit line was used.

GERDAU S.A. 

NOTES TO THE CONDENSED CONSOLIDATED INTERIM FINANCIAL STATEMENTS 

as of June 30, 2026 

(In thousands of Brazilian Reais – R$, unless otherwise stated) 

(Unaudited)

The Company and its subsidiaries are not subject to default clauses (covenants) linked to financial ratios. Non-financial performance clauses have been complied with.

b) Main amortization

In February 2026, the subsidiaries Gerdau Açominas S.A. and Gerdau Aços Longos S.A. fully settled debts contracted with a top-tier institution in the total amount of R$ 300 million, plus approximately R$ 18.6 million in interest.

NOTE 13 – DEBENTURES

Maturities of long-term amounts are as follows:

The debentures are denominated in Brazilian Reais, nonconvertible, and pay variable interest as a percentage of the CDI – Interbank Deposit Certificate. The Company and its subsidiaries are not subject to default clauses (covenants) linked to financial indexes.

The average interest rate was CDI + 0.58% for the year ended on June 30, 2026 (CDI + 0.58% for the year ended on June 30, 2025).

NOTE 14 - FINANCIAL INSTRUMENTS