# EDGAR Filing Document

**Accession Number:** 0001073404
**File Stem:** 0001104659-26-074110
**Filing Date:** 2026-6
**Character Count:** 5333
**Document Hash:** 5124de709068d554b072821165849621
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001104659-26-074110.hdr.sgml**: 20260615

**ACCESSION NUMBER**: 0001104659-26-074110

**CONFORMED SUBMISSION TYPE**: 6-K

**PUBLIC DOCUMENT COUNT**: 3

**CONFORMED PERIOD OF REPORT**: 20260615

**FILED AS OF DATE**: 20260615

**DATE AS OF CHANGE**: 20260615

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** GERDAU S.A.
- **CENTRAL INDEX KEY:** 0001073404
- **STANDARD INDUSTRIAL CLASSIFICATION:** STEEL WORKS, BLAST FURNACES & ROLLING & FINISHING MILLS [3310]
- **ORGANIZATION NAME:** 04 Manufacturing
- **EIN:** 000000000
- **STATE OF INCORPORATION:** D5
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** 6-K
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-14878
- **FILM NUMBER:** 261091825

**BUSINESS ADDRESS:**
- **ADDRESS IS A NON US LOCATION:** YES
- **STREET 1:** AV DOUTORA RUTH CARDOSO, 8,501
- **STREET 2:** 8TH FLOOR
- **CITY:** SAO PAULO, SP
- **PROVINCE COUNTRY:** D5
- **ZIP:** 05425-070
- **BUSINESS PHONE:** 011-55-51-3323-2703

**MAIL ADDRESS:**
- **ADDRESS IS A NON US LOCATION:** YES
- **STREET 1:** AV DOUTORA RUTH CARDOSO, 8,501
- **STREET 2:** 8TH FLOOR
- **CITY:** SAO PAULO, SP
- **PROVINCE COUNTRY:** D5
- **ZIP:** 05425-070

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** GERDAU SA
- **DATE OF NAME CHANGE:** 19981112

**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 June 15, 2026

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 ⌧ Form 40-F ◻

Exhibit Index

<u>Exhibit</u> <u>Description of Exhibit</u> <br>[99.1](tm2618001d1_ex99-1.htm) [Notice to the Market – Binding Proposal for Acquisition of Equity Stake](tm2618001d1_ex99-1.htm)

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: June 15, 2026

---

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

---

## Exhibit 99.1

**Exhibit 99.1**

![](tm2618001d1_6kimg01.jpg)

**GERDAU S.A.**

Corporate Tax ID (CNPJ/MF): 33.611.500/0001-19

Registry (NIRE): 35300520696

**NOTICE TO THE MARKET**

**Gerdau S.A.** (B3: GGBR / NYSE: GGB) ("Company") hereby informs its shareholders and the market in general that it has submitted a binding proposal and, on this date, entered into a Share Purchase Agreement with Companhia Paranaense de Energia ("COPEL") for the acquisition of COPEL's entire equity interest in Dona Francisca Energética S.A. ("DFESA"), corresponding to 23.03% of its share capital. The transaction implies an enterprise value of R$150 million.

The purchase price will be paid in cash on the closing date, using the Company's own available resources and is subject to customary closing adjustments in accordance with the terms and conditions set forth in the definitive agreements. Additionally, the closing of the transaction is subject to the satisfaction of customary conditions precedent for transactions of this nature, including approval by the Brazilian antitrust authority.

Additionally, the transaction includes the waiver by COPEL of its right of first refusal in connection with the acquisition by the Company of the equity interest held by Centrais Elétricas de Santa Catarina ("CELESC"), as disclosed in the Notice to the Market dated April 16, 2026.

DFESA is a privately held corporation engaged in electric power generation. It holds an 85% ownership interest in the concession consortium of the Dona Francisca Hydroelectric Power Plant, located on the Jacuí River, in the State of Rio Grande do Sul, between the municipalities of Agudo and Nova Palma. The plant has an installed capacity of 125 MW and firm energy of 72.5 average MW, of which approximately 66 average MW are allocated to DFESA.

Currently, Gerdau holds 53.94% of DFESA's share capital, corresponding to 35.6 average MW of energy. After completion of the acquisition of the interests held by CELESC and COPEL, which will occur upon the fulfillment of the conditions precedent and the receipt of the required approvals, the Company will hold 100% of DFESA's share capital through a total investment of R$300 million in enterprise value, increasing its self-generation capacity by 30.4 average MW. As a result, Gerdau will utilize the full 65.94 average MW of firm energy available at DFESA for self-generation purposes.

The acquisition is aligned with Gerdau's capital allocation discipline, enhancing cost competitiveness across its businesses and increasing self-generation to more than 50% of its energy consumption, with a focus on renewable energy and in line with the Company's previously disclosed decarbonization strategy.

São Paulo, June 15, 2026.

**Rafael Dorneles Japur**

Vice-President and

Investor Relations Officer