Exhibit 99.1

NOTICE TO THE MARKET

Gerdau S.A. issues US$650 million 4.875% bonds due 2027 through its subsidiary Gerdau Trade Inc.

Gerdau S.A. (B3: GGBR, NYSE: GGB, Latibex: XGGB) announces that it has launched and priced, on October 12, 2017, ten-year bonds in the international capital markets through its wholly-owned subsidiary Gerdau Trade Inc. The bonds will be unconditionally and irrevocably guaranteed by Gerdau S.A., Gerdau Açominas S.A., Gerdau Aços Longos S.A. and Gerdau Aços Especiais S.A.

Final terms and conditions:

Issuer		Gerdau Trade Inc.

Guarantors		Gerdau S.A., Gerdau Açominas S.A., Gerdau Aços Longos S.A. and Gerdau Aços Especiais S.A.

Ratings		S&P: BBB- / Fitch: BBB-

Principal Amount		US$650,000,000

Format		Rule 144A / Reg S

Trade Date		October 12, 2017

Settlement Date		October 24, 2017 (T+8)

Maturity		October 24, 2027

Interest Payment Dates		April 24 and October 24, commencing April 24, 2018

Coupon		4.875%, semi-annual in arrears; 30/360 count basis

Clearing		The Depository Trust Company (DTC) / Euroclear / Clearstream

Listing		Luxembourg Stock Exchange (Euro MTF)

The geographic distribution of the offering is as follows: 39% United States; 39% Europe, Middle East and Africa; 10% Latin America; and 12% Asia-Pacific. The majority of buyers of the bonds were Fund Managers, Private Banks, Insurance Companies and banks. The net proceeds from the offering will be used to refinance the Company’s indebtedness and for general corporate purposes.

This notice shall not constitute an offer to sell or a solicitation of an offer to buy, nor shall there be any sale of the bonds in any state or jurisdiction in which such offer, solicitation or sale would be unlawful. The bonds will be offered to qualified institutional buyers in reliance on Rule 144A under the Securities Act of 1933, as amended, and to non-U.S. persons in offshore transactions outside the United States in accordance with Regulation S thereunder. The bonds have not been registered under the Securities Act or any state securities laws, and may not be offered or sold in the United States or to U.S. persons absent registration or an applicable exemption from the registration requirements.