COMPANHIA SIDERÚRGICA NACIONAL
Publicly Held Company
Corporate Taxpayer’s ID 33.042.730/0001-04
NIRE 35-3.0039609.0

MATERIAL FACT

COMPANHIA SIDERÚRGICA NACIONAL (“Company”) announces that the Board of Directors approved its 15th issuance of simple debentures, not convertible into shares, unsecured, in up to three series, in the total amount of R$ 800,000,000.00 (eight hundred million reais), with a nominal unitary value of R$ 1,000.00, on the date of issuance (“Debentures” and “Issuance”, respectively).

The Issuance will be the subject of a public offering, under the rite of automatic registration, in accordance with Law No. 6,385, of December 7, 1976, as amended, Resolution of the Brazilian Securities and Exchange Commission (“CVM”) No. 160, of July 13, 2022, as amended, and other applicable legal and regulatory provisions, under the firm placement guarantee regime, intended for qualified investors, as provided for in article 12 of CVM Resolution No. 30, of May 11, 2021, as amended (“Offer”). The Debentures will meet the requirements of article 2 of Law No. 12,431, of June 24, 2011, as amended, so that their holders will be entitled to tax benefits in accordance with the law.

Within the scope of the Offer, the procedure for collecting investment intentions will be adopted, organized by the Coordinators, in accordance with the terms to be set out in the deed of issuance of the Debentures ("Deed of Issuance") and in the distribution contract to be signed between the Company and Coordinators receiving reserves, observing the provisions of article 61, paragraph 2, of CVM Resolution 160, to (i) define the final remuneration rate; (ii) define the number of Debentures to be allocated in each series, observing the maximum volume of Debentures in the Second Series; and (iii) verify the existence of demand for the placement of all series of Debentures, and, if such demand is verified, decide on the Issuance in up to 2 (two) series (“Bookbuilding Procedure”).

The First Series Debentures will have a maturity period of 10 (ten) years, counting from the date of issuance. Remunerative interest will be accrued on the updated nominal unitary value of the First Series Debentures corresponding to a certain percentage per year, to be defined in accordance with the Bookbuilding Procedure, and which will be the highest rate between (a) the internal rate of return of the Security Public Treasury IPCA+ with Semiannual Interest (new denomination of National Treasury Notes – Series B) (“NTN-B”), due on May 15, 2033, calculated in accordance with the indicative quote published by ANBIMA on its website (http://www.anbima.com.br) on the date of completion of the Bookbuilding Procedure, exponentially increased by an annual surcharge (spread) of 0.55% (fifty-five hundredths percent) per year, base 252 (two hundred and fifty-two) Business Days, and (b) 6.20% (six whole and twenty hundredths percent) per year, based on 252 (two hundred and fifty-two) Business Days.

The Second Series Debentures will have a maturity period of 15 (fifteen) years, counting from the date of issuance. Remunerative interest will be accrued on the updated nominal unitary value of the Second Series Debentures corresponding to a certain percentage per year, to be defined in accordance with the Bookbuilding Procedure, and which will be the highest rate between (a) the internal rate of return of the NTN -B, maturing on May 15, 2035, calculated in accordance with the indicative price published by ANBIMA on its website (http://www.anbima.com.br) on the date of the Bookbuilding Procedure, plus exponentially with an annual surcharge (spread) of 0.70% (seventy hundredths percent) per year, based on 252 (two hundred and fifty-two) Business Days, and (b) 6.40% (six whole forty hundredths percent) per year, based on 252 (two hundred and fifty-two) Business Days.

Pursuant to article 2, paragraph 1, of Law 12,431, Decree 11,964 and Resolution of the National Monetary Council No. 5,034, of July 21, 2022, the net resources raised by the Company through the Debentures will be used exclusively for the future payment and/or reimbursement of expenses, expenses and/or debts related to the implementation of the infrastructure investment project in the logistics and transport sector, including railways, including locomotives and wagons, as long as they occurred within a period equal to or less than 24 ( twenty-four) months from the closing date of the Offer.

The general conditions of the Issuance are indicated in the minutes of the Company's Board of Directors Meeting, which is available on the Company's investor relations page and on the CVM website on the world wide web.

This Material Fact is disclosed by the Company exclusively in compliance with applicable legislation and regulations, in a manner that is exclusively informative in nature and should not be interpreted or considered, for all legal purposes, as a sales or offering material for the Debentures.

São Paulo, April 12, 2024.

Antonio Marco Campos Rabello

Executive of Finance and Investor Relations Pursuant to the requirements 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.

COMPANHIA SIDERÚRGICA NACIONAL

This press release may contain forward-looking statements. These statements are statements that are not historical facts, and are based on management's current view and estimates of future economic circumstances, industry conditions, company performance and financial results. The words "anticipates", "believes", "estimates", "expects", "plans" and similar expressions, as they relate to the company, are intended to identify forward-looking statements. Statements regarding the declaration or payment of dividends, the implementation of principal operating and financing strategies and capital expenditure plans, the direction of future operations and the factors or trends affecting financial condition, liquidity or results of operations are examples of forward-looking statements. Such statements reflect the current views of management and are subject to a number of risks and uncertainties. There is no guarantee that the expected events, trends or results will actually occur. The statements are based on many assumptions and factors, including general economic and market conditions, industry conditions, and operating factors. Any changes in such assumptions or factors could cause actual results to differ materially from current expectations.