6-K

FORM 6-K

U.S. SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

REPORT OF FOREIGN PRIVATE ISSUER

PURSUANT TO RULE 13a-16 OR 15d-16 UNDER THE

SECURITIES EXCHANGE ACT OF 1934

Dated August 27, 2018

Commission File Number 1-14878

GERDAU S.A.

(Exact Name as Specified in its Charter)

N/A

(Translation of Registrant’s Name)

Av. das Nações Unidas, 8,501 — 8° andar

São Paulo, São Paulo - Brazil CEP 05425-070

(Address of principal executive offices)

Indicate by check mark whether the registrant files or will file annual reports under cover Form 20-F or Form 40-F.

Form 20-F x           Form 40-F  o

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(1): o

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(7): o

Indicate by check mark whether by furnishing the information contained in this Form, the registrant is also thereby furnishing the information to the Commission pursuant to Rule 12g3-2(b) under the Securities Exchange Act of 1934.

Yes o        No x

If “Yes” is marked, indicate below the file number assigned to the registrant in connection with Rule 12g3-2(b):  Not applicable.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused the Report to be signed on its behalf by the undersigned, thereunto duly authorized.

Date:  August 27, 2018

GERDAU S.A.
By:	/s/ Harley Lorentz Scardoelli
Name:	Harley Lorentz Scardoelli
Title:	Investor Relations Director

2

EXHIBIT INDEX

Exhibit	Description of Exhibit
99.1	Notice to the Market, August 27, 2018

3

EX-99.1

Exhibit 99.1

GERDAU S.A.

CNPJ/MF n.º 33.611.500/0001-19

NOTICE TO THE MARKET

Gerdau S.A. (“Company”) hereby informs its shareholders and the general market that, on August 24, 2018, it signed an agreement to sell its participation interest in Gerdau Hungria KFT Y CIA Sociedad Regular Colectiva, a subsidiary of the Company located in Spain and owner of 98,89% of Gerdau Steel India Ltd. shares, to Blue Coral Investment Holdings Pte. Ltd and Mountainpeak Investment Holdings Ltd.. The transaction perimeter involves 100% of the operations and assets in India, including the special steels industrial unit located in Tadipatri, with annual installed capacity of 250 thousand tonnes of crude steel and 300 thousand tonnes of rolled steel.

The enterprise value of the transaction corresponds to US$120 million, subject to the typical adjustments. The consummation of the transaction is subject to typical settlement conditions and is expected to occur by the end of 2018.

The transaction will enable Gerdau to focus more on managing its strategic assets in the Americas, where its key markets, Brazil and the United States, are located.

Advisors

Citigroup Global Markets Inc is serving as the exclusive financial advisor to Gerdau.

São Paulo, August 27, 2018.

Harley Lorentz Scardoelli

Executive Vice-President

Investor Relations Officer