6-K

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 6-K

Report of Foreign Issuer

Pursuant To Rule 13a-16 Or 15d-16 of the

Securities Exchange Act of 1934

For the month of February 2025

Commission File Number: 333-251238

COSAN S.A.

(Exact name of registrant as specified in its charter)

N/A

(Translation of registrant’s name into English)

Av. Brigadeiro Faria Lima, 4100, – 16th floor São Paulo, SP 04538-132 Brazil (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 ☐

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):

Yes ☐ No ☒

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):

Yes ☐ No ☒

COSAN S.A.

Corporate Taxpayer ID (CNPJ): 50.746.577/0001-15

Company Registry (NIRE): 35.300.177.045

Publicly Held Company

CVM 19836

NOTICE TO THE MARKET

COSAN S.A. (B3: CSAN3; NYSE: CSAN) (“Cosan” or “Company”) informs its shareholders and the market in general that the Board of Directors, in a meeting held on February 4, 2025, approved the engagement of PricewaterhouseCoopers Auditores Independentes Ltda ("PwC") to provide independent auditing services for the Company, replacing BDO RCS Auditores Independentes SS Ltda., which has expressed its consent to the substitution.

The engagement of PwC was finalized after a competitive process to obtain the best market conditions, streamlining, and efficiency of the audit process for the Group as a whole.

PwC will commence its activities with the review of the quarterly information for the first quarter of 2025 and will also conduct audit work for the Company's subsidiaries, including notably Rumo, Compass, and Moove, and their respective subsidiaries and affiliates.

São Paulo, February 11, 2025.

Rodrigo Araujo Alves

Chief Financial and Investor Relations Officer

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: February 11, 2025