SABESP CEO exercises 50,295 RSUs, updates holdings

COMPANHIA DE SANEAMENTO BASICO DO ESTADO DE SAO PAULO-SABESP CEO Leone Piani Carlos Augusto reported equity compensation activity involving Common Shares and Restricted Stock Units (RSUs).

Rhea-AI Filing Summary

COMPANHIA DE SANEAMENTO BASICO DO ESTADO DE SAO PAULO-SABESP CEO Leone Piani Carlos Augusto reported equity compensation activity involving Common Shares and Restricted Stock Units (RSUs). He exercised derivative awards covering 50,295 RSUs into 50,295 Common Shares and, in a related move, 13,831 Common Shares were disposed of as a tax-withholding payment at $6.69 per share. After these transactions, his directly held Common Shares increased to 64,703, and an additional 14,408 Common Shares are reported as indirectly owned through his spouse. A prior grant of 1,005,951 RSUs vests in tranches from May 1, 2026 through May 1, 2033, each RSU representing the right to receive one Common Share upon vesting.

Insider Trade Summary

50,295 shares exercised/converted

Exercise 4 txns

Insider Leone Piani Carlos Augusto

Role CEO

Type	Security	Shares	Price	Value
Exercise	Restricted Stock Units	50,295	$0.00	$0.00
Exercise	Common Shares	50,295	$0.00	$0.00
Exercise Price or Tax Liability	Common Shares	13,831	$6.69	$93K
holding	Common Shares	--	--	--

Holdings After Transaction: Restricted Stock Units — 955,656 contracts (Direct); Common Shares — 36,464 shares (Direct); Common Shares — 14,408 shares (Indirect, Spouse)

Footnotes (1)

1. F1. On April 29, 2025, the reporting person was granted an aggregate of 1,005,951 restricted stock units ("RSUs"), vesting on May 1, 2026, May 1, 2027, May 1, 2028, May 1, 2029, May 1, 2030, May 1, 2031, May 1, 2032 and May 1, 2033, subject to continued service as an officer of the issuer. Each RSU represents the contingent right to receive one Common Share of the Issuer upon vesting.

Key Figures

RSUs exercised: 50,295 shares Tax-withholding shares: 13,831 shares at $6.69 Direct holdings after transactions: 64,703 Common Shares +3 more

6 metrics

RSUs exercised 50,295 shares Common Shares acquired via derivative exercise on May 1, 2026

Tax-withholding shares 13,831 shares at $6.69 Common Shares delivered for tax/exercise obligations on May 1, 2026

Direct holdings after transactions 64,703 Common Shares Direct ownership following May 1, 2026 events

Indirect holdings via spouse 14,408 Common Shares Indirect ownership reported as of May 1, 2026

RSU grant size 1,005,951 RSUs Grant dated April 29, 2025 vesting 2026–2033

Exercise price for RSUs $0.00 per RSU Conversion of RSUs into Common Shares on May 1, 2026

Key Terms

Restricted Stock Units, tax-withholding disposition, derivative exercise/conversion, indirect ownership

4 terms

Restricted Stock Units financial

"the reporting person was granted an aggregate of 1,005,951 restricted stock units ("RSUs")"

Restricted stock units are a type of company reward where employees are promised shares of stock, but they only fully own these shares after meeting certain conditions, like staying with the company for a set time. They matter because they can become valuable assets and are often used to motivate employees to help the company succeed.

tax-withholding disposition financial

"transaction_action": "tax-withholding disposition""

A tax-withholding disposition is an event or transaction—such as selling or transferring securities, exercising options, or receiving compensation—that triggers a requirement to hold back part of the payment and remit it to tax authorities. It matters to investors because it reduces the cash they receive immediately and can change the timing and amount of taxable income, like a cashier taking a portion of your sale proceeds to pay taxes before you get the rest.

derivative exercise/conversion financial

"transaction_action": "derivative exercise/conversion""

indirect ownership financial

"ownership_type": "indirect""

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What did SABESP (SBS) CEO Leone Piani report in this Form 4?

The CEO reported an equity compensation event. He exercised 50,295 restricted stock units into Common Shares and 13,831 shares were disposed of to cover tax or exercise obligations, while his direct and indirect share holdings were updated accordingly.

How many SABESP (SBS) shares did the CEO acquire and dispose in this filing?

He exercised derivative awards to acquire 50,295 Common Shares and had 13,831 Common Shares disposed of as a tax-withholding payment. The net effect was an increase in directly held Common Shares, with no open-market buy or sell reported.

What is the CEO’s SABESP (SBS) share ownership after these transactions?

After the reported transactions, he directly holds 64,703 Common Shares and indirectly holds 14,408 Common Shares through his spouse. These figures reflect the updated ownership position following the RSU exercise and related tax-withholding disposition.

What price was used for the SABESP (SBS) tax-withholding share disposition?

The tax-withholding disposition involved 13,831 Common Shares at $6.69 per share. This disposition represents shares delivered to satisfy exercise price or tax liabilities, not an open-market sale initiated for investment reasons.

What longer-term RSU grant does the SABESP (SBS) CEO hold?

He was granted 1,005,951 restricted stock units vesting annually from May 1, 2026 through May 1, 2033. Each RSU, upon vesting, entitles him to receive one SABESP Common Share, subject to continued service as an officer.

Does this SABESP (SBS) Form 4 show open-market buying or selling by the CEO?

No open-market buy or sell is reported. The filing shows a derivative exercise converting RSUs into Common Shares and a tax-withholding share disposition, which is a mechanistic step to cover obligations rather than a discretionary market trade.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Accepted by SEC EDGAR 05/15/2026 - 01:38 PM EDT Learn about SEC filing dates

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^*

Leone Piani Carlos Augusto

(Last) (First) (Middle)

300 COSTA CARVALHO STREET

(Street)

SAO PAULO 05429-900

(City) (State) (Zip)

BRAZIL

(Country)

2. Issuer Name and Ticker or Trading Symbol
COMPANHIA DE SANEAMENTO BASICO DO ESTADO DE SAO PAULO-SABESP [ SBSP3 ]

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

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

2a. Foreign Trading Symbol
[SBS]

3. Date of Earliest Transaction (Month/Day/Year)
05/01/2026

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 Shares	05/01/2026		M		50,295	A	(1)	64,703	D
Common Shares	05/01/2026		F		13,831	D	$6.69	36,464	D
Common Shares								14,408	I	Spouse

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
Restricted Stock Units	(1)	05/01/2026		M			50,295	(1)	(1)	Common Shares	50,295	$0	955,656	D

Explanation of Responses:

1. On April 29, 2025, the reporting person was granted an aggregate of 1,005,951 restricted stock units ("RSUs"), vesting on May 1, 2026, May 1, 2027, May 1, 2028, May 1, 2029, May 1, 2030, May 1, 2031, May 1, 2032 and May 1, 2033, subject to continued service as an officer of the issuer. Each RSU represents the contingent right to receive one Common Share of the Issuer upon vesting.

Remarks:

All amounts reported in this Form 4 reflect certain recent events exempt from reporting under Section 16(a), namely (i) the receipt of rights to receive dividend equivalents (the accrual of which in this Form 4 upon vesting of the RSUs); (ii) the capital increase that occurred in March 2026; and (iii) the stock split approved by the Issuer's shareholders in April 2026. Due to the issuer's status as a foreign private issuer pursuant to Rule 3a12-3(b) under the Securities Exchange Act of 1934 (the "Act"), the reporting person's transactions in the issuer's equity securities are exempt from Sections 16(b) and 16(c) of the Act.

	/s/ Beatriz Caroline de Sousa Daher, as attorney-in-fact for Carlos Augusto Leone Piani	05/15/2026
	** 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)