[Form 4] Cosan S.A. Insider Trading Activity

Rhea-AI Filing Summary

Cosan S.A. director Mello Rubens Ometto Silveira, through an associated entity, reported an indirect open-market sale of 77,640 shares of Common Stock at $3.44 per share. These shares were held indirectly through Rio das Pedras Acoes, which reported zero shares following the transaction.

The filing also shows large indirect holdings in Cosan through other entities, with 109,532,616 shares held via Queluz Holdings Limited and 712,702,674 shares held via Aguassanta Participacoes S.A. Common stock is represented by American Depositary Shares, with each ADS equal to four Common shares.

Insider Trade Summary

Net Seller: 77,640 shares ($267,082)

Net Sell 3 txns

Insider Mello Rubens Ometto Silveira

Role null

Sold 77,640 shs ($267K)

Type	Security	Shares	Price	Value
Sale	Common Stock	77,640	$3.44	$267K
holding	Common Stock	--	--	--
holding	Common Stock	--	--	--

Holdings After Transaction: Common Stock — 0 shares (Indirect, Rio das Pedras Acoes)

Footnotes (1)

1. [object Object]

Key Figures

Shares sold: 77,640 shares Sale price: $3.44 per share Indirect holding via Queluz: 109,532,616 shares +3 more

6 metrics

Shares sold 77,640 shares Indirect open-market sale via Rio das Pedras Acoes

Sale price $3.44 per share Price for 77,640 Common shares sold

Indirect holding via Queluz 109,532,616 shares Total shares following transaction, held indirectly

Indirect holding via Aguassanta 712,702,674 shares Total shares following transaction, held indirectly

ADS to Common ratio 1 ADS : 4 shares Each ADS represents four Common shares

Shares remaining at Rio das Pedras 0 shares Total shares following the 77,640-share sale

Key Terms

open-market sale, American Depositary Shares, indirect ownership, transaction code

4 terms

open-market sale financial

"transaction_code_description: Sale in open market or private transaction"

An open-market sale is when a shareholder sells existing shares directly on a public exchange to any willing buyer, rather than through a private deal. Think of it like putting goods on a busy market stall where price is set by supply and demand; for investors it matters because such sales increase available supply, can put short-term downward pressure on the stock price, and signal changes in liquidity or investor confidence.

American Depositary Shares financial

"Common stock represented by American Depositary Shares."

American depositary shares (ADSs) are a way for investors in the United States to buy shares of foreign companies without dealing with international markets directly. They represent ownership in a foreign company's stock and are traded on U.S. stock exchanges, making it easier for American investors to buy, sell, and own parts of companies from around the world.

indirect ownership financial

"ownership_type: indirect; nature_of_ownership: Rio das Pedras Acoes"

transaction code regulatory

"transaction_code_description: Unknown transaction code"

Form 4 Insider Transactions: What Each Field Means →

SEC Form 4

FORM 4

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

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Mello Rubens Ometto Silveira

(Last) (First) (Middle)

AVENIDA BRIGADEIRO FARIA LIMA 4100

(Street)

SAO PAULO SP 04543132

(City) (State) (Zip)

BRAZIL

(Country)

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

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

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

2a. Foreign Trading Symbol
[CSAN3]

3. Date of Earliest Transaction (Month/Day/Year)
05/22/2026

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

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

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

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock(1)	05/22/2026		S		77,640	D	$3.44	0	I	Rio das Pedras Acoes
Common Stock								712,702,674	I	Aguassanta Participacoes S.A.
Common Stock(1)								109,532,616	I	Queluz Holdings Limited

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:

1. Common stock represented by American Depositary Shares. Each American Depositary Share represents four shares of Common Stock.

	/s/ Rubens Ometto Silveira Mello	05/26/2026
	** 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 4 (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 4: SEC 1474 (03-26)