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 October 2024

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

MATERIAL FACT

Cosan S.A. (B3: CSAN3; NYSE: CSAN) (“Cosan” or “Company”), informs its shareholders and the market in general that its Board of Directors approved, on the date hereof, changes of Cosan’s Executive Officers.

Nelson Gomes will take over as CEO of Raízen S.A.. Marcelo Eduardo Martins, current Chief Strategy Officer, will take over as CEO of Cosan. And Ricardo Mussa will serve as CEO of Cosan Investimentos.

The changes will be effective on November 1st, 2024.

São Paulo, October 21st, 2024

Rodrigo Araujo AlvesChief 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: October 21, 2024