Exhibit 99.1

GERDAU S.A.

Condensed consolidated interim financial statements

as of June 30, 2025

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, 2025

(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, activities which expanded the product mix and made its operations even more competitive. 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 July 31, 2025.

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 period ended on June 30, 2025 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, 2024, 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, 2024.

Starting with the disclosure of the results of 2025, the Company began to disclose the information and results of its business segments as follows:

· Brazil Segment: includes the long, flat and special steel operations and the iron ore operation located in Brazil and and joint ventures (note 3.2) and associates (note 3.3) companies located in Brazil.

· North America Segment: includes the long and specialty steel operations located in Canada and the United States and the joint ventures (note 3.2) located in Canada and Mexico;

· South America Segment: includes the operations in Argentina, Peru and Uruguay.

With these changes, the information and results of the former Special Steel Segment, which included the special steel operations located in Brazil and the United States, will now be disclosed jointly with the other segments, according to their geographic location, as the Brazil Segment and the North America Segment, respectively.

This new format for disclosing information and results is in line with recent changes in the global steel industry scenario, which have led to an increasing regionalization of markets, business dynamics and local currencies of these operations, improving the presentation of Gerdau's results in Brazil and North America, the main regions in which it operates. The comparative information of the segments presented in this Interim Information has been adjusted to reflect this new composition.

GERDAU S.A.

NOTES TO THE CONDENSED CONSOLIDATED INTERIM FINANCIAL STATEMENTS

as of June 30, 2025

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

(Unaudited)

2.2 – New accounting standards

The issued and/or reviewed IFRS standards made by the IASB that are effective for the year started in 2025 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 2026 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 of IFRS 19 – Subsidiaries without Public Accountability: Disclosures. Establishes simplified disclosures requirements for consolidated or individual financial statements of entities eligible for the application of this standard. These rules are effective for fiscal years beginning on/or after January 1, 2027. The Company does not expect material impacts on its Financial Statements.

- Amendment to IFRS 9 and IFRS 7 – Amendments to the classification and measurement of financial instruments. It clarifies aspects related to the classification and measurement of financial instruments. This amendment to the standards is effective for years beginning on/or after January 1, 2026. The Company is evaluating the impacts on its Financial Statements of adopting these standards.

- Amendment to IFRS 9 and IFRS 7 – Contracts that refer to electricity dependent on nature. Clarifies aspects related to the application and disclosure of purchase and sale contracts exposed to variations in electricity generation dependent on uncontrollable natural conditions and related financial instruments. This amendment to the standards is effective for fiscal years beginning on or after January 1, 2026. The Company does not expect significant impacts on its Financial Statements.

- Annual improvements to IFRS Accounting Standards. It applies amendments to IFRS 1, addressing first-adoption aspects related to hedge accounting; IFRS 7, covering aspects of gain and loss on the reversal of a financial instrument, credit risk disclosures, and the difference between fair value and transaction price; IFRS 9, addressing aspects related to the reversal of leasing liabilities and transaction price; IFRS 10, addressing the determination of the “de facto agent” and IAS 7, addressing aspects related to the cost method. These amendments are effective for years beginning on/or after January 1, 2026. The Company does not expect material impacts on its Financial Statements.

2.3 - Increased tariffs on exports to the United States

Following the announcement by the United States government of an increase in tariffs on exports of products from Brazil, the Company has been monitoring, carefully, the potential effects that the U.S. tariffs on Brazil could have on the domestic market, such as a ripple effect on the consumption of steel in Brazil.

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, 2025, when compared to those existing on December 31, 2024, except in relation to the acquisition of control of Gerdau Summit Aços Fundidos e Forjados S.A., Rio do Sangue Energia S.A., Comercial Gerdau Aços Planos Ltda. e Paranatinga Energia S.A., described in Note 3.4.

GERDAU S.A.

NOTES TO THE CONDENSED CONSOLIDATED INTERIM FINANCIAL STATEMENTS

as of June 30, 2025

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

(Unaudited)

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.

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:

GERDAU S.A.

NOTES TO THE CONDENSED CONSOLIDATED INTERIM FINANCIAL STATEMENTS

as of June 30, 2025

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

(Unaudited)

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.

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 other shareholders that prevent the Company from fully implementing decisions regarding the conduct of the affiliate’s business.

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

3.4 — Acquisition of company control

a) Gerdau Summit Aços Fundidos e Forjados S.A. (Gerdau Summit)

On February 10, 2025, the Company, after fulfilling all the conditions precedent, including approval by the antitrust authorities, concluded the transaction with Sumitomo Corporation and The Japan Steel Works Ltd., for the acquisition of 39.53% and 1.74%, respectively, of the total shares issued by Gerdau Summit Aços Fundidos e Forjados S.A. (“Gerdau Summit”). With the closing of the transaction, the Company owns 100% of the Gerdau Summit’s capital. The acquisition price, paid in cash with own resources, was approximately US$ 32.6 million (equivalent to R$ 188.6 million on the date of completion of the transaction), and as a result of the acquisition, the Company obtained a gain from a bargain purchase of R$ 37.7 million, due to the acquisition price being lower than the fair value of Gerdau Summit, with the gain being recognized in the income statement of the period. Gerdau Summit is located in Pindamonhangaba, in the state of São Paulo, and produces cast and forged steel, especially for the production of cylinders and axles in the steel, aluminum, sugar and ethanol and energy sectors. The transaction is in line with the Company’s strategy of generating greater synergy between its businesses and offering higher value- added products and services to its customers. Gerdau Summit, until then a joint venture, with this transaction becomes a subsidiary of the Company.

GERDAU S.A.

NOTES TO THE CONDENSED CONSOLIDATED INTERIM FINANCIAL STATEMENTS

as of June 30, 2025

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

(Unaudited)

On May 30, 2025, at the Extraordinary General Meeting, it was decided to incorporate Gerdau Summit into Gerdau S.A., without a capital increase and without the issuance of new shares by the Company, with effect from May 31, 2025.

The Company assessed the fair value of Gerdau Summit's assets and liabilities and the following table summarizes the fair value of assets and liabilities on the date of acquisition of control of the company:

The amounts recognized as net revenue and net income for the six-month period ended June 30, 2025, presented in the Income Statement, attributable to Gerdau Summit, total R$ 322.7 million and R$21.1 million, respectively.

b) Rio do Sangue Energia S.A.

On March 21, 2025, the Company completed the acquisition, from Atiaia Energia S.A., of all the shares of Rio do Sangue Energia S.A., owner of the Small Hydroelectric Power Plant (“PCH”) called Garganta da Jararaca, for R$ 244.5 million. The acquisition price was paid in cash on the closing date with its own available resources. The PCH is located in the state of Mato Grosso and will supply renewable energy to Gerdau's steel production units in Brazil, on a self-generation basis. The acquisition of these assets is in line with the Company's strategy of increasing the cost competitiveness of its business by increasing the self-production of clean energy, and in line with the previously announced decarbonization process. The amounts recognized as revenue and net income for the year attributable to Rio do Sangue Energia S.A., included in the Company's Consolidated Financial Statements since the acquisition date, are not material. Additionally, the revenues and net profit that would be generated by Rio do Sangue Energia S.A. for the six-month period ended June 30, 2025, if control had been obtained at the beginning of the year, would also not be significant.

c) Comercial Gerdau Aços Planos Ltda.

On April 11, 2025, the Company acquired 100% of the capital of Kloeckner Metals Brasil Ltda. from Klöeckner & Co.SE, for approximately R$ 42.9 million. As a result of the acquisition, the Company realized a gain on a bargain purchase of R$ 3.6 million, since the acquisition price was lower than the fair value of the acquired company, and the gain was recognized in the income statement for the period. The acquisition price was paid in cash with available equity. Following the acquisition, the Company changed the name of its new subsidiary to Comercial Gerdau Aços Planos Ltda.. The acquired company's business purpose is the sale of steel products and metal cutting and bending, among other activities. The amounts recognized as revenue and net income for the year, attributable to Comercial Gerdau Aços Planos Ltda., included in the Company's Consolidated Financial Statements since the acquisition date, are not material. Additionally, the revenues and net profit that would have been generated by Comercial Gerdau Aços Planos Ltda. for the six-month period ended June 30, 2025, if control had been obtained at the beginning of the year, would also not have been significant.

GERDAU S.A.

NOTES TO THE CONDENSED CONSOLIDATED INTERIM FINANCIAL STATEMENTS

as of June 30, 2025

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

(Unaudited)

d) Paranatinga Energia S.A.

On April 28, 2025, the Company, together with Atiaia Energia S.A., completed the acquisition of all the shares of Paranatinga Energia S.A., owner of the Small Hydroelectric Power Plant (PCH) called Paranatinga II, for approximately R$197.2 million, net of consolidated cash of R$ 32.8 million. The acquisition price was paid in cash with its own available resources. This SHP is located in the state of Mato Grosso and will supply renewable energy to Gerdau's steel production units in Brazil, on a self-production basis. The acquisition of this asset is in line with Gerdau's strategy of increasing the cost competitiveness of its business by increasing the self-production of clean energy, and in line with the decarbonization process already announced by the Company. The amounts recognized as revenue and net income for the year, attributable to Paranatinga Energia S.A., included in the Company's Consolidated Financial Statements since the acquisition date, are not material. Additionally, the revenues and net profit that would be generated by Paranatinga Energia S.A. for the six-month period ended June 30, 2025, if control had been obtained at the beginning of the year, would also not be significant.

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, 2025

(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, 2025 and 2024. The foreign subsidiaries of the Company are subject to taxation at rates ranging between 23% and 35%. 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.

GERDAU S.A.

NOTES TO THE CONDENSED CONSOLIDATED INTERIM FINANCIAL STATEMENTS

as of June 30, 2025

(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:

The Company did not recognize a portion of tax assets regarding tax losses and negative social contribution from some operations in Brazil in the amount of R$ 312,292 (R$ 300,763 on December 31, 2024), which do not have an expiration date. The subsidiaries abroad had R$ 794,210 (R$ 849,200 as of December 31, 2024) of tax credits on capital losses for which deferred tax assets have not been recognized and which expire between 2029 and 2035 and also several tax losses of state credits in the amount of R$ 272,757 (R$ 326,966 as of December 31, 2024), which expire at various dates between 2031 and 2038.

GERDAU S.A.

NOTES TO THE CONDENSED CONSOLIDATED INTERIM FINANCIAL STATEMENTS

as of June 30, 2025

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

(Unaudited)

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, 2025, acquisitions amounted to R$ 1,600,298 (R$ 1,419,775 as of June 30, 2024), and disposals amounted to R$ 17,478 (R$ 21,045 as of June 30, 2024). During the six-month period ended on June 30, 2025, acquisitions amounted to R$ 2,977,034 (R$ 2,278,096 as of June 30, 2024), and disposals amounted to R$ 30,872 (R$ 26,313 as of June 30, 2024).

The additions to property, plant and equipment in the six-month period ended on June 30, 2025 include a non-cash effect amounted to R$ 521,116 (R$ 24,444 as of June 30, 2024).

b) Capitalized borrowing costs – borrowing costs capitalized during the three-month period ended on June 30, 2025 amounted to R$ 58,187 (R$ 35,385 as of June 30, 2024). Borrowing costs capitalized during the six-month period ended on June 30, 2025 amounted to R$ 89,106 (R$ 65,147 as of June 30, 2024).

c) Guarantees – no property, plant and equipment were pledged as collateral for loans and financing on June 30, 2025 and December 31, 2024.

NOTE 10 – GOODWILL

The changes in goodwill are as follows:

The amounts of goodwill by segment are as follows:

GERDAU S.A.

NOTES TO THE CONDENSED CONSOLIDATED INTERIM FINANCIAL STATEMENTS

as of June 30, 2025

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

(Unaudited)

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, 2025 and December 31, 2024, contracts negotiated via letter of credit had a payment term of up to 180 days and rates that also varied, depending on market conditions.

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:

GERDAU S.A.

NOTES TO THE CONDENSED CONSOLIDATED INTERIM FINANCIAL STATEMENTS

as of June 30, 2025

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

(Unaudited)

As of June 30, 2025, the nominal weighted average cost of debts denominated in US dollars is 5.64% p.a. (5.52% p.a. on December 31, 2024), for debts denominated in Real of CDI + 0.21% p.a. (CDI + 0.82% p.a. on December 31, 2024) and for other currencies 4.11% p.a. (3.88% p.a. on December 31, 2024).

Loans and financing, denominated in Reais, are substantially adjusted at a fixed rate or 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, 2025, the amounts represents dates from July 1, 2026 to December 31, 2026.

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$ 4,775 million as of June 30, 2025) 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, 2025, no amount of this credit line was used.

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) Debt collection

In February 2025, the subsidiary Gerdau Açominas S.A. raised debt in the amount of R$ 1,165 millions from a first-class financial institution, with maturity in December of the same year.

In March 2025, the Company entered into an addendum to the financing agreement with the Superintendence for the Development of the Central-West Region (SUDECO), brokered by a first-class financial institution, with the total approved amount of approximately R$ 301 million. As of June 30, 2025, the amount actually released to the Company was R$ 93.9 million, with provision for the release of other funds up to the limit of the total amount stipulated in the agreement, depending on the progress of the projects for which the financing is intended. The contract matures in July 2044.

In April 2025, the subsidiary Gerdau Açominas S.A. raised debt backed by export contracts for approximately R$ 303 million from a first-class financial institution, with a maturity date of December 2025.

In April 2025, the subsidiary Gerdau Aços Longos raised debt backed by agricultural activities for R$ 750 million from a first-class financial institution, with a maturity date of October 2027. Furthermore, in May 2025, the Company restructured a R$ 428 million debt, due in 2025, from USD to EUR. This last transaction was accompanied by the contracting of a derivative financial instrument with a protective nature, the purpose of which is to index the cost of the debt to the CDI rate.

GERDAU S.A.

NOTES TO THE CONDENSED CONSOLIDATED INTERIM FINANCIAL STATEMENTS

as of June 30, 2025

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

(Unaudited)

In June 2025, the subsidiary Gerdau Trade Inc. raised a bond maturing in June 2035 in the amount of US$ 650 million (equivalent to R$ 3,624 million on the date of the bond issue). Part of the proceeds, in the amount of US$ 238 million (equivalent to R$ 1,327 million on the date of the repurchase), were allocated to the repurchase of part of the Company's bonds whose original maturity was in October 2027. The financial expense incurred in this repurchase, in the amount of R$ 39,646, was recorded in the “Buyback of bonds” line in the Income Statement.

c) Assumption of Obligations by Incorporation

As described in Note 3.4, in June 2025, Gerdau S.A. incorporated its subsidiary Gerdau Summit Aços Fundidos e Forjados S.A., fully assuming its assets and liabilities. Among the obligations assumed, a debt of R$ 60 million maturing in January 2026.

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 104.48% of the CDI + 0.67% for the three and six-month periods ended on June 30, 2025 (CDI + 0.62% for the three and six-month periods ended on June 30, 2024, respectively).

In June 2025, the Company announced the public offering for its 19th debenture issuance, issuing 1,375 (one million, three hundred and seventy-five thousand) debentures in registered, book-entry form, without issuing warrants or certificates, with a unit face value of R$ 1, totaling R$ 1.375 billion. In the same month, the Company carried out the early settlement of its 16th debenture issuance, in the amount of R$ 800 million.

NOTE 14 - FINANCIAL INSTRUMENTS

a) General considerations - Gerdau S.A. and its subsidiaries enter into transactions with financial instruments whose risks are managed through market strategies discussed and shared with senior management and in accordance with internal guidelines and control systems for exposure limits to them. All financial instruments are recorded in the accounting books and presented as short-term investments, trade accounts receivable, related parties (assets and liabilities), fair value of derivatives (assets and liabilities), other current assets, other non-current assets, trade accounts payable – domestic market, trade accounts payable – debtor risk, trade accounts payable - imports, loans and financing, debentures, other current liabilities and other non-current liabilities.

GERDAU S.A.

NOTES TO THE CONDENSED CONSOLIDATED INTERIM FINANCIAL STATEMENTS

as of June 30, 2025

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

(Unaudited)

The Company has derivatives and non-derivative instruments, such as the hedge for some operations under hedge accounting. These operations are intended to protect the Company against exchange rate fluctuations on foreign currency loans, interest rate and commodity prices fluctuations. These transactions are carried out considering direct active or passive exposures, without leverage.

b) Fair Value — the Fair Value of the financial instruments is as follows:

The fair values of Loans and Financing and Debentures are based on market premises, which may take into consideration discounted cash flows using equivalent market rates and credit rating. All other financial instruments, which are recognized in the Consolidated Financial Statements at their carrying amount, are substantially similar to those that would be obtained if they were traded in the market. However, because there is no active market for these instruments, differences could exist if they were settled in advance. The fair value hierarchy of the financial instruments above is presented in Note 14.g.

c) Risk factors that could affect the Company’s and its subsidiaries’ businesses:

Price risk of commodities: this risk is related to the possibility of changes in prices of the products sold by the Company or in prices of raw materials and other inputs used in the productive process. Since the Company operates in a commodity market, net sales and cost of sales may be affected by changes in the international prices of their products or materials. In order to minimize this risk, the Company constantly monitors the price variations in the domestic and international markets. Furthermore, the Company may contract derivatives in order to reduce this risk.

Interest rate risk: this risk arises from the effects of fluctuations in interest rates applied to the Company’s financial liabilities or assets and future cash flows and income. The Company evaluates its exposure to these risks: (i) comparing financial assets and liabilities denominated at fixed and floating interest rates and (ii) monitoring the variations of interest rates like Secured Overnight Financing Rate (SOFR) and CDI. Accordingly, the Company may enter into interest rate swaps in order to reduce this risk.

Exchange rate risk: this risk is related to the possibility of fluctuations in exchange rates affecting the amounts of financial assets or liabilities or of future cash flows and income. The Company assesses its exposure to the exchange rate by measuring the difference between the amount of its assets and liabilities in foreign currency. The Company understands that the accounts receivables originated from exports, its cash and cash equivalents denominated in foreign currencies and its investments abroad are more than equivalent to its liabilities denominated in foreign currency. Since the management of these exposures occurs at each operation level, if there is a mismatch between assets and liabilities denominated in foreign currency, the Company may contract derivative financial instruments in order to mitigate the effect of exchange rate fluctuations.

GERDAU S.A.

NOTES TO THE CONDENSED CONSOLIDATED INTERIM FINANCIAL STATEMENTS

as of June 30, 2025

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

(Unaudited)

Credit risk: this risk arises from the possibility of the Company not receiving amounts arising from sales to customers or investments made with financial institutions. In order to minimize this risk, the Company adopt the procedure of analyzing in details of the financial position of their customers, establishing a credit limit and constantly monitoring their balances. Regarding financial investments, the Company only carries out transactions with first-rate institutions and with low credit risk, as assessed by rating agencies and risk mitigation parameters defined in the Company’s internal guidelines.

Capital management risk: this risk comes from the Company’s choice in adopting a financing structure for its operations. The Company manages its capital structure, which consists of a ratio between the financial debts and its own capital (Net Equity) based on internal policies and benchmarks. The Key Performance Indicators (KPI) related to the “Capital Structure Management” objective are: WACC (Weighted Average Cost of Capital), Net Debt/EBITDA (Earnings before interest, income tax, depreciation and amortization), Coverage Ratio of Net Financial Expenses (EBITDA/Net Financial Expenses) and Debt/Total Capitalization Ratio. Net Debt is formed by the principal of the debt reduced by cash, cash equivalents and short-term investments (notes 4, 12 and 13). Total Capitalization is formed by the Total Debt (composed of the principal of the debt) and the Net Equity (Note 17). The Company may change its capital structure, according to economic and financial conditions, in order to optimize its financial leverage and debt management. At the same time, the Company seeks to improve its ROCE (Return on Capital Employed) through the implementation of working capital management and an efficient program of investments in property, plant and equipment. In the long term, the Company seeks to remain within the parameters below, admitting occasional variations in the short term:

These key indicators are used to monitor objectives described above and may not necessarily be used as indicators for other purposes, such as impairment tests.

Liquidity risk: The Company’s management policy of indebtedness and cash on hand is based on using the committed lines and the currently available credit lines with or without a guarantee in export receivables for maintaining adequate levels of short, medium, and long-term liquidity. The maturity of long-term loans and financing, and debentures are presented in Notes 12 and 13, respectively.

Sensitivity analysis:

The Company performed a sensitivity analysis, which can be summarized as follows: