SABESP officer exercises 8,243 RSUs, pays taxes in shares

COMPANHIA DE SANEAMENTO BASICO DO ESTADO DE SAO PAULO-SABESP operations and maintenance officer Debora Pierini Longo exercised 8,243 restricted stock units into Common Shares on May 1, 2026.

Rhea-AI Filing Summary

COMPANHIA DE SANEAMENTO BASICO DO ESTADO DE SAO PAULO-SABESP operations and maintenance officer Debora Pierini Longo exercised 8,243 restricted stock units into Common Shares on May 1, 2026. To cover tax obligations, 2,267 Common Shares were withheld at $6.69 per share. After these transactions, she directly holds 5,976 Common Shares and 24,729 restricted stock units from a 32,965-unit grant awarded on April 29, 2025, which vests in equal portions on May 1 of 2026, 2027, 2028 and 2029.

Insider Trade Summary

8,243 shares exercised/converted

Exercise 3 txns

Insider Pierini Longo Debora

Role Operations & Maint. Officer

Type	Security	Shares	Price	Value
Exercise	Restricted Stock Units	8,243	$0.00	$0.00
Exercise	Common Shares	8,243	$0.00	$0.00
Exercise Price or Tax Liability	Common Shares	2,267	$6.69	$15K

Holdings After Transaction: Restricted Stock Units — 24,729 contracts (Direct); Common Shares — 5,976 shares (Direct)

Footnotes (1)

1. F1. On April 29, 2025, the reporting person was granted an aggregate of 32,965 restricted stock units ("RSUs"), vesting pro rata on each of May 1, 2026, May 1, 2027, May 1, 2028 and May 1, 2029, 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: 8,243 shares Tax-withholding shares: 2,267 shares Tax-withholding price: $6.69 per share +3 more

6 metrics

RSUs exercised 8,243 shares Restricted stock units converted to Common Shares on May 1, 2026

Tax-withholding shares 2,267 shares Common Shares withheld to pay taxes on May 1, 2026

Tax-withholding price $6.69 per share Value used for the 2,267-share tax-withholding disposition

Common Shares after transaction 5,976 shares Direct SABESP Common Share holdings following reported transactions

RSUs remaining 24,729 units Restricted stock units held after converting 8,243 units

Original RSU grant 32,965 units Grant awarded on April 29, 2025, vesting annually 2026–2029

Key Terms

Restricted Stock Units, tax-withholding disposition, derivative exercise/conversion, Exercise or conversion of derivative security

4 terms

Restricted Stock Units financial

"the reporting person was granted an aggregate of 32,965 restricted stock units ("RSUs"), vesting pro rata"

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" for 2,267 Common Shares at $6.69"

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" for 8,243 restricted stock units"

Exercise or conversion of derivative security financial

"transaction_code_description: "Exercise or conversion of derivative security""

FAQ

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

What insider transaction did SABESP (SBS) report for Debora Pierini Longo?

SABESP reported that officer Debora Pierini Longo exercised 8,243 restricted stock units into Common Shares on May 1, 2026. As part of the same event, 2,267 shares were withheld to satisfy tax obligations, leaving her with 5,976 Common Shares held directly afterward.

How many SABESP (SBS) shares were withheld for taxes in this Form 4?

The filing shows 2,267 Common Shares were withheld at $6.69 per share to cover tax liabilities. This tax-withholding disposition is coded as an “F” transaction and is not an open-market sale, but a mechanism to pay taxes on vested equity.

How many SABESP (SBS) shares did the officer acquire through RSU vesting?

Debora Pierini Longo acquired 8,243 Common Shares through the exercise of restricted stock units coded as an “M” derivative exercise. Each vested RSU converted into one Common Share, reflecting a scheduled equity compensation event rather than a market purchase.

What are Debora Pierini Longo’s SABESP (SBS) holdings after the reported transactions?

After the May 1, 2026 transactions, she directly holds 5,976 SABESP Common Shares. She also continues to hold 24,729 restricted stock units, which represent additional potential Common Shares as they vest under the original grant’s four-year vesting schedule.

What are the terms of the SABESP (SBS) restricted stock unit grant mentioned in the Form 4?

On April 29, 2025, she was granted 32,965 restricted stock units, vesting pro rata on May 1 of 2026, 2027, 2028 and 2029. Each RSU gives the contingent right to receive one SABESP Common Share upon vesting, subject to continued service as an officer.

Does this SABESP (SBS) Form 4 show any open-market share sales or purchases?

The Form 4 does not show open-market buys or sells. It reports an RSU exercise for 8,243 shares and a tax-withholding disposition of 2,267 shares. Both transactions are compensation-related and tied to equity vesting and associated tax payments.

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

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Accepted by SEC EDGAR 05/15/2026 - 01:44 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^*

Pierini Longo Debora

(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)
	Operations & Maint. Officer

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		8,243	A	(1)	8,243	D
Common Shares	05/01/2026		F		2,267	D	$6.69	5,976	D

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			8,243	(1)	(1)	Common Shares	8,243	$0	24,729	D

Explanation of Responses:

1. On April 29, 2025, the reporting person was granted an aggregate of 32,965 restricted stock units ("RSUs"), vesting pro rata on each of May 1, 2026, May 1, 2027, May 1, 2028 and May 1, 2029, 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 Debora Pierini Longo	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)