SEC FORM 3

SEC FORM 3SEC Form 3

FORM 3

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

INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

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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1. Name and Address of Reporting Person^*

Rosenberg Whitaker Carneiro Ralph Gustavo

(Last)

(First)

(Middle)

RUA LEOPOLDO COUTO MAGALHAES JUNIOR

822, 1ST FLOOR

(Street)

SAO PAULO

04542-000

(City)

(State)

(Zip)

BRAZIL

(Country)

2. Date of Event Requiring Statement (Month/Day/Year)
03/18/2026

3. Issuer Name and Ticker or Trading Symbol
Cosan S.A. [ CSAN ]

3a. Foreign Trading Symbol
[CSAN3]

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

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

X	Director	10% Owner
	Officer (give title below)	Other (specify below)

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

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

Table I - Non-Derivative Securities Beneficially Owned
1. Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)
COMMON STOCK (CSAN3)⁽¹⁾	4,251,582	I	CLASSE A DO PERFIN RALLY FUNDO DE INVESTIMENTO EM PARTICIPACOES MULTIESTRATEGIA RESP LIMITADA

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
1. Title of Derivative Security (Instr. 4)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)

Explanation of Responses:

1. Mr. Carneiro owns common stock of Cosan S.A. through the investment fund, Classe A do Perfin Rally Fundo de Investimento em Participacoes Multiestrategia Responsabilidade Limitada. Mr. Carneiro disclaims beneficial ownership of the shares held by the investment fund except to the extent, if any, of his pecuniary interest therein.

	/s/ Ralph Gustavo Rosenberg Whitaker Carneiro	03/18/2026
	** 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 5 (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 3: SEC 1473 (03-26)

SEC Form 3 filed by new insider Rosenberg Whitaker Carneiro Ralph Gustavo