Gerdau S.A. (GGB) details conclusion of share buyback in Form 6-K

Rhea-AI Filing Summary

Gerdau S.A. filed a Form 6-K as a foreign private issuer, furnishing a material fact related to the conclusion of its share buyback program. The report is dated December 19, 2025 and identifies an exhibit describing the buyback program’s completion, signed by the Vice-President and Investor Relations Officer.

Form 6-K: How Foreign Companies Report to the SEC →

U.S. SECURITIES AND EXCHANGE COMMISSION 

Washington, D.C. 20549

FORM 6-K

REPORT OF FOREIGN PRIVATE ISSUER 

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

SECURITIES EXCHANGE ACT OF 1934

Dated December 19, 2025

Commission File Number 1-14878

GERDAU S.A. 

(Translation of Registrant’s Name into English)

Av. Dra. Ruth Cardoso, 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 of Form 20-F or Form 40-F.

Form 20-F  x           Form 40-F  ¨ 

Exhibit Index

Exhibit		Description of Exhibit
99.1		Material Fact – Buyback program conclusion

SIGNATURES

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.

Date: December 19, 2025

	GERDAU S.A.
	By:	/s/ Rafael Dorneles Japur
	Name:	Rafael Dorneles Japur
	Title:	Vice-President and Investor Relations Officer

FAQ

What does Gerdau S.A. (GGB) report in this Form 6-K?

Gerdau S.A. reports a Form 6-K furnishing a material fact about the conclusion of its share buyback program. The filing is administrative in nature and points investors to an attached exhibit for detailed information on the program’s completion.

What is the main exhibit in Gerdau S.A.’s Form 6-K?

The main exhibit is labeled "Material Fact – Buyback program conclusion." This exhibit is intended to describe key information regarding the completion of Gerdau S.A.’s share repurchase program, although specific terms and amounts are not included in the excerpt provided.

When is Gerdau S.A.’s Form 6-K regarding the buyback conclusion dated?

The Form 6-K is dated December 19, 2025. This date indicates when Gerdau S.A. formally furnished the report and the related material fact about its buyback program conclusion to the U.S. Securities and Exchange Commission for investor disclosure.

Who signed Gerdau S.A.’s Form 6-K on the buyback program conclusion?

The Form 6-K was signed on behalf of Gerdau S.A. by Rafael Dorneles Japur, Vice-President and Investor Relations Officer. His signature confirms the company’s authorization of the filing and its attached material fact regarding the buyback program’s completion.

What type of annual report does Gerdau S.A. file with the SEC?

Gerdau S.A. indicates that it files its annual reports under cover of Form 20-F. This confirms its status and reporting framework as a foreign private issuer complying with U.S. disclosure requirements applicable to non-U.S. companies listed in the United States.