# EDGAR Filing Document

**Accession Number:** 0001430162
**File Stem:** 0001554855-25-002360
**Filing Date:** 2025-12
**Character Count:** 4273
**Document Hash:** 663c3061c0b8dd1c7b1993ec8b80f000
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001554855-25-002360.hdr.sgml**: 20251231

**ACCESSION NUMBER**: 0001554855-25-002360

**CONFORMED SUBMISSION TYPE**: 6-K

**PUBLIC DOCUMENT COUNT**: 3

**CONFORMED PERIOD OF REPORT**: 20251230

**FILED AS OF DATE**: 20251231

**DATE AS OF CHANGE**: 20251230

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Cosan S.A.
- **CENTRAL INDEX KEY:** 0001430162
- **STANDARD INDUSTRIAL CLASSIFICATION:** RETAIL-AUTO DEALERS & GASOLINE STATIONS [5500]
- **ORGANIZATION NAME:** 07 Trade & Services
- **EIN:** 000000000
- **STATE OF INCORPORATION:** D5
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** 6-K
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-40155
- **FILM NUMBER:** 251615484

**BUSINESS ADDRESS:**
- **STREET 1:** AV. BRIGADEIRO FARIA LIMA
- **STREET 2:** 4100, 16TH FLOOR
- **CITY:** SAO PAULO, SP
- **STATE:** D5
- **ZIP:** 04538-132
- **BUSINESS PHONE:** 55-11-3897-9797

**MAIL ADDRESS:**
- **STREET 1:** AV. BRIGADEIRO FARIA LIMA
- **STREET 2:** 4100, 16TH FLOOR
- **CITY:** SAO PAULO, SP
- **STATE:** D5
- **ZIP:** 04538-132

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** Cosan S.A. Industria e Comercio
- **DATE OF NAME CHANGE:** 20080319

**UNITED STATES**

**SECURITIES AND EXCHANGE COMMISSION**

**Washington, D.C. 20549**

FORM 6-K

**REPORT OF FOREIGN PRIVATE ISSUER PURSUANT TO RULE 13a-16<br>OR 15d-16 UNDER THE SECURITIES EXCHANGE ACT OF 1934**

For the month of December 2025

**Commission File Number: 001-40155**<br>

**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, – 16**th **floor**<br>São Paulo, SP 04538-132 Brazil<br>(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 X Form 40-F  

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**COSAN S.A.**

CNPJ No. 50.746.577/0001-15<br>NIRE 35.300.177.045<br>Publicly Held Company<br>CVM Code 19836

**<u>MATERIAL FACT</u>**

**COSAN S.A. (B3: CSAN3; NYSE: CSAN)** ("<u>Cosan</u>" or "<u>Company</u>"), in compliance with CVM Resolution No. 44, dated August 23, 2021, informs its shareholders and the market in general that, on this date, Banco Bradesco BBI S.A. ("<u>Bradesco BBI</u>") and Banco BTG Pactual S.A. ("<u>BTG Pactual</u>") have acquired, in equal proportions, preferred shares issued by Cosan Dez Participações S.A. ("<u>Cosan Dez</u>") for a total amount of R$4 billion. These shares correspond, in terms of equity value, to approximately 23% of Cosan Dez's total share capital and jointly grant political rights equivalent to 9.98% of the voting capital (the "<u>Transaction</u>").

Cosan Dez is the vehicle that holds the shares of Compass Gás e Energia S.A. ("<u>Compass</u>") owned by the Company. The Transaction represents a renegotiation of the financial terms of the structure established between the Company and Bradesco BBI in 2022. Regarding the conditions agreed upon in the context of the Transaction, the Company granted Bradesco BBI and BTG Pactual a put option on the shares of Cosan Dez held by these investors, exercisable in one or more opportunities, on a staggered basis, starting from the 5th, 6th, and 7th anniversaries of the Transaction, which allowed the Company to reduce the financial cost associated with the previous transaction. In addition, the Transaction follows the Company's ongoing strategy to optimize liabilities following the recent capitalization.

With the closing of the Transaction, the corporate structure of Cosan Dez and Compass will be as follows:

![Image2](c317d63fc5105badddc1.jpg)

São Paulo, December 30, 2025

**Rafael Bergman**

Chief Financial and Investor Relations Officer

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**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: December 30, 2025

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| | |
|:---|:---|
| &nbsp;&nbsp; COSAN S.A. | &nbsp;&nbsp; COSAN S.A. |
| &nbsp;&nbsp; By: | /s/ Rafael Bergman |
|  | Name:Rafael Bergman |
|  | Title:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Chief Financial Officer |

---