COMPANHIA SIDERÚRGICA NACIONAL Publicly-Held Company Corporate Taxpayer's ID (CNPJ/MF): 33.042.730/0001-04 NOTICE TO THE MARKET

National Steel Company-CSN (BOVESPA: CSNA3; NYSE: SID) (the "Company") informs that it has not been able to publish its audited financial statements as of and for the year ended December 31, 2016 and has not filed its annual report on Form 20-F for 2016 yet. As a result, the Company is not currently in compliance with its reporting obligations under U.S. Securities and Exchange (SEC) and New York Stock Exchange (NYSE) regulations.

The Company is working with its external auditors on certain accounting and disclosure matters related to the business combination that occurred on November 30, 2015, by which the Company's subsidiary, CSN Mineração S.A. (formerly Congonhas Minérios S.A.), acquired control of Nacional Minerios S.A. (Namisa). In addition, the Company's audit committee is in final stages of an internal investigation of an allegation published in the press in April 2017 concerning an alleged illicit payment of R$16.5 million during the construction of its long-steel plant in Volta Redonda. The company's audit committee has mandated well-known external counsel and advisor to conduct the investigation and no indication of any misconduct has been identified to date.

The company currently does not have an estimated filing date, but is using its best efforts to finalize its financial statements and file its Form 20-F as soon as possible.

São Paulo, May 24, 2017.

David Moise Salama Investor Relations Executive Officer

CSN - Companhia Siderúrgica Nacional published this content on 24 May 2017 and is solely responsible for the information contained herein.
Distributed by Public, unedited and unaltered, on 24 May 2017 22:59:18 UTC.

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