New Sabesp (NYSE: SBS) director Affonso Mateus files initial Form 3

Rhea-AI Filing Summary

COMPANHIA DE SANEAMENTO BASICO DO ESTADO DE SAO PAULO-SABESP reported an initial ownership filing for director Affonso Bandeira Mateus on Form 3. This filing lists him as a director of the company but does not report any insider stock transactions or derivative holdings in the provided data.

SEC Form 3

FORM 3

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

INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

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

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1. Name and Address of Reporting Person^*

Affonso Bandeira Mateus

(Last) (First) (Middle)

300 COSTA CARVALHO STREET

(Street)

SAO PAULO 05429-900

(City) (State) (Zip)

BRAZIL

(Country)

2. Date of Event Requiring Statement (Month/Day/Year)
03/18/2026

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

3a. Foreign Trading Symbol

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

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

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

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

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

Table I - Non-Derivative Securities Beneficially Owned
1. Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:

Remarks:

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. Exhibit 24 - Power of Attorney.

No securities are beneficially owned.

	/s/ Beatriz Caroline de Sousa Daher, as attorney-in-fact for Mateus Affonso Bandeira	03/18/2026
	** 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 5 (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 3: SEC 1473 (03-26)

FAQ

What does the Sabesp (SBS) Form 3 for Affonso Bandeira Mateus show?

The Form 3 shows that Affonso Bandeira Mateus is a director of Sabesp. It is an initial ownership statement and, in the provided data, does not list any stock or derivative transactions or positions.

Does the Sabesp (SBS) Form 3 report any insider share purchases or sales?

No, the provided Form 3 data for Sabesp director Affonso Bandeira Mateus reports no insider purchases or sales. The transaction summary lists zero buy, sell, exercise, gift, tax withholding, or restructuring transactions.

Who is the reporting person on the Sabesp (SBS) Form 3 filing?

The reporting person is Affonso Bandeira Mateus, identified as a director of COMPANHIA DE SANEAMENTO BASICO DO ESTADO DE SAO PAULO-SABESP. He is not flagged as an officer or 10% owner in the provided data.

Are there any derivative securities reported in the Sabesp (SBS) Form 3?

No derivative securities are reported in the provided Form 3 data. The derivativeSummary is empty, and the transaction summary shows zero derivative transactions, indicating no options or similar instruments disclosed here.

What is the significance of a Form 3 filing for Sabesp (SBS)?

A Form 3 is an initial statement of beneficial ownership for insiders such as directors. For Sabesp, this filing formally records Affonso Bandeira Mateus as a director and establishes a baseline for any future Form 4 or Form 5 transaction reports.