Cosan (NYSE: CSAN) prepares secondary sale of Compass shares after spin-off

Rhea-AI Filing Summary

Cosan S.A. reports that documentation for a secondary public offering of common shares of Compass Gás e Energia S.A., held by Cosan and other shareholders, has been disclosed in Brazil’s unorganized over-the-counter market. Within this offering, Cosan may sell Shares representing approximately 15% of Compass’s share capital, with the final amount and price per Share to be set through a bookbuilding procedure.

To enable Cosan’s participation as a selling shareholder, a partial and disproportionate spin-off of Cosan Dez Participações S.A. was completed, transferring spun-off net equity to Compass. As a result, Compass issued 142,838,019 new common shares to Cosan, corresponding to about 20% of Compass’s share capital, now held directly by Cosan with no change to Cosan’s own share capital or shareholders’ equity.

Insights

Equity capital markets analyst

Cosan restructures its Compass stake and prepares for a sizable secondary sale.

Cosan is organizing a secondary public offering of Compass shares in Brazil’s over-the-counter market, where it may dispose of Shares representing about 15% of Compass’s share capital. This is a liquidity event for existing holders rather than a primary capital raise for Compass.

To participate as a selling shareholder, Cosan completed a partial and disproportionate spin-off of Cosan Dez, leading Compass to issue 142,838,019 new common shares to Cosan, equal to roughly 20% of Compass’s share capital. Cosan’s interest in Compass becomes a direct 20% stake, with no change to Cosan’s own share capital or shareholders’ equity, so the restructuring is mainly about ownership path and potential monetization rather than altering Cosan’s balance sheet in this disclosure.

Key Figures

Potential Compass stake for sale: Approximately 15% of share capital New Compass shares issued to Cosan: 142,838,019 shares Cosan direct stake in Compass: Approximately 20% of share capital

3 metrics

Potential Compass stake for sale Approximately 15% of share capital Shares Cosan may dispose of in Compass secondary offering

New Compass shares issued to Cosan 142,838,019 shares Common shares issued after Cosan Dez spin-off

Cosan direct stake in Compass Approximately 20% of share capital Equity interest held by Cosan after restructuring

Key Terms

secondary public offering, Bookbuilding Procedure, partial and disproportionate spin-off, unorganized over-the-counter market, +2 more

6 terms

secondary public offering financial

"in connection with the secondary public offering of common shares issued by Compass"

A secondary public offering is when a company sells additional shares to the public after its initial sale, often to raise more money or allow early investors to cash out. For investors, it can impact the stock's price by increasing the number of shares available, potentially making the stock more or less valuable depending on demand.

Bookbuilding Procedure financial

"The effective number of shares ... will be determined through the Bookbuilding Procedure."

partial and disproportionate spin-off financial

"the partial and disproportionate spin-off of Cosan Dez Participações S.A. was also completed"

unorganized over-the-counter market financial

"The offering will be carried out in Brazil, in the unorganized over-the-counter market"

Material Fact regulatory

"MATERIAL FACT COSAN S.A. (B3: CSAN3; NYSE: CSAN) (“Cosan” or the “Company”)"

CVM Resolution No. 160 regulatory

"The offering will be carried out in Brazil ... pursuant to CVM Resolution No. 160"

Form 6-K: How Foreign Companies Report to the SEC →

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 6-K

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

For the month of April 2026

Commission File Number: 001-40155

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 X Form 40-F

COSAN S.A.

CNPJ No. 50.746.577/0001-15

NIRE 35.300.177.045

Publicly Held Company

CVM Code 19836

MATERIAL FACT

COSAN S.A. (B3: CSAN3; NYSE: CSAN) (“Cosan” or the “Company”), pursuant to CVM Resolution No. 44 and Article 157, paragraph 4, of Brazilian Law No. 6,404/76, and further to the Material Facts disclosed on February 23, 2026 and March 5, 2026, hereby informs its shareholders and the market in general that, on this date, the documentation in connection with the secondary public offering of common shares issued by Compass Gás e Energia S.A. (“Compass” and the “Shares”, respectively) and held by the Company and the other selling shareholders identified in the Preliminary Brazilian Prospectus, was disclosed. The offering will be carried out in Brazil, in the unorganized over-the-counter market, pursuant to CVM Resolution No. 160 (the “Offering”).

Within the context of the Offering, Cosan may dispose of Shares representing approximately 15% of the share capital of Compass, considering the placement of the Shares included in the base offering, any additional tranche and any supplementary tranche, as applicable. The effective number of shares held by Cosan to be sold will be determined through the Bookbuilding Procedure.

The price per Share will be determined on the pricing date of the Offering, based on the outcome of the bookbuilding procedure.

In order to enable the Company’s participation in the Offering as a selling shareholder, the partial and disproportionate spin-off of Cosan Dez Participações S.A. (“Cosan Dez”) was also completed on this date, with the transfer of the spun-off net equity to Compass. As a result of the transaction, Compass issued 142,838,019 new common shares in favor of the Company, corresponding to approximately 20% of Compass’s share capital, a stake that had previously been indirectly held by the Company through Cosan Dez. Accordingly, the Company now directly holds a 20% equity interest in Compass, with no change to the Company’s share capital or shareholders’ equity.

The Company and Compass will keep the market duly informed of any developments relating to the matters described herein.

This Material Fact is disclosed for informational purposes only, pursuant to applicable regulation, and does not constitute an offer to sell or a solicitation of an offer to purchase any of the Shares. No securities issued by the Company or by Compass may be offered or sold in the United States of America unless such securities are registered or exempt from registration under the U.S. Securities Act of 1933, as amended, or any other applicable securities laws. This Material Fact also does not constitute an offer to sell or a solicitation of an offer to purchase any securities, in Brazil or abroad, including in the United States or in any other jurisdiction. The Offering and the Shares will not be registered with any securities regulatory authority of any jurisdiction other than Brazil, solely with the CVM and ANBIMA. Furthermore, under no circumstances should this Material Fact be considered and/or construed as, nor does it constitute, an investment recommendation or an offer to sell or the solicitation of an offer to buy any securities issued by the Company or by Compass.

São Paulo, April 27, 2026

 Rafael Bergman

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:  April 27, 2026

	COSAN S.A.
	By:	/s/ Rafael Bergman
		Name:            Rafael Bergman
		Title: Chief Financial Officer

FAQ

What did Cosan S.A. (CSAN) announce regarding Compass Gás e Energia?

Cosan announced disclosure of documentation for a secondary public offering of Compass Gás e Energia common shares it holds. The offering will occur in Brazil’s unorganized over-the-counter market, with Cosan participating as a selling shareholder alongside other identified investors.

How much of Compass’s share capital may Cosan sell in this secondary offering?

Cosan may dispose of Shares representing approximately 15% of Compass’s share capital through the secondary public offering. The exact number of shares and final price per Share will be determined by a bookbuilding procedure conducted as part of the transaction.

What corporate restructuring did Cosan complete to join the Compass offering?

Cosan completed a partial and disproportionate spin-off of Cosan Dez Participações S.A., transferring spun-off net equity to Compass. This step enabled Cosan to participate directly as a selling shareholder in the Compass offering described in the Material Fact communication.

How did the spin-off affect Cosan’s ownership in Compass Gás e Energia?

Following the spin-off, Compass issued 142,838,019 new common shares to Cosan, equal to about 20% of Compass’s share capital. Cosan now directly holds this 20% equity interest in Compass, replacing its previous indirect ownership through Cosan Dez.

Did Cosan’s own share capital or shareholders’ equity change with this transaction?

Cosan stated that its own share capital and shareholders’ equity did not change as a result of the spin-off and share issuance. The main effect is a reorganization of how Cosan holds its interest in Compass, now directly rather than through Cosan Dez.

Where will the Compass secondary offering be registered and carried out?

The Compass offering will be carried out in Brazil’s unorganized over-the-counter market under CVM Resolution No. 160. The offering and Shares will be registered only with Brazilian regulators CVM and ANBIMA, and not registered with securities authorities in other jurisdictions.