SEC FORM 4

SEC FORM 4SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

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Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Johannpeter Claudio

(Last)

(First)

(Middle)

AVENUE DOUTORA RUTH DE CARDOSO, 8501

8TH FLOOR, PINHEIROS

(Street)

SAO PAULO

05425-070

(City)

(State)

(Zip)

BRAZIL

(Country)

2. Issuer Name and Ticker or Trading Symbol
GERDAU S.A. [ GGB ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

Director		10% Owner
Officer (give title below)	X	Other (specify below)
		Vice-Chairman of Board

2a. Foreign Trading Symbol
[GGBR]

3. Date of Earliest Transaction (Month/Day/Year)
09/23/2026

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

4. If Amendment, Date of Original Filed (Month/Day/Year)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	Code	V	Amount	(A) or (D)	Price		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
Preferred shares	09/23/2026		S		85,607	D	$4.94⁽¹⁾	0	D
Common shares								702,952,615	I	Remarks⁽⁵⁾
Preferred shares								283	I	Preferred shares held by an immediate family member (relationship: son).

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	8. Price of Derivative Security (Instr. 5)		10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
Restricted Stock Units	$3.79⁽¹⁾							02/12/2027⁽²⁾	02/12/2027	Preferred shares	106,519		106,519	D
Restricted Stock Units	$3.56⁽¹⁾							02/12/2028⁽³⁾	02/12/2028	Preferred shares	116,745		116,745	D
Restricted Stock Units	$4.05⁽¹⁾							02/12/2029⁽⁴⁾	02/12/2029	Preferred shares	105,670		105,670	D

Explanation of Responses:

1. The price is denominated in Brazilian reais and has been translated into U.S. dollars at the September 23, 2026 selling rate of R$5.1414 per US$1.00, as reported by the Central Bank of Brazil.

2. Restricted stock units vest on February 12, 2027.

3. Restricted stock units vest on February 12, 2028.

4. Restricted stock units vest on February 12, 2029.

5. The Reporting Person has a 20% interest in Klapar Participacoes S.A.. Klapar Participacoes S.A holds a 25% equity interest in INDAC - Investimentos e Participacoes S.A. INDAC owns 57% of Grupo Gerdau Empreendimentos Ltda. INDAC holds 100% of Acoter Participacoes Ltda. Acoter Participacoes Ltda. owns the remaining 43% of Grupo Gerdau Empreendimentos Ltda. Grupo Gerdau Empreendimentos Ltda., together with INDAC, jointly controls Gerdau Metalurgica S.A. The Reporting Person disclaims beneficial ownership of the reported securities except to the extent of their pecuniary interest therein, and the inclusion of these shares in this report shall not be deemed an admission of beneficial ownership of all of the reported shares for purposes of Section 16 or for any other purpose.

	/s/Claudio Johannpeter	09/25/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
* Form 4: SEC 1474 (03-26)