UNITED STATES

SECURITIES AND EXCHANGECOMMISSION

Washington, D.C.20549

FORM 6-K

Report of Foreign PrivateIssuer
Pursuant to Rule 13a-16 or 15d-16 of the

Securities ExchangeAct of 1934

For the month ofAugust, 2025

Commission File Number1-15106

PETRÓLEO BRASILEIROS.A. – PETROBRAS

(Exact name of registrantas specified in its charter)

Brazilian PetroleumCorporation – PETROBRAS

(Translation of Registrant'sname into English)

Avenida Henrique Valadares, 28 – 9th floor 
20231-030 – Rio de Janeiro, RJ
Federative Republic of Brazil

(Address of principalexecutive office)

Indicate by check markwhether the registrant files or will file annual reports under cover Form 20-F or Form 40-F. 

Form 20-F ___X___ Form40-F _______

Indicate by check markwhether the registrant by furnishing the information contained in this Form is also thereby furnishing the information to the Commissionpursuant to Rule 12g3-2(b) under the Securities Exchange Act of 1934.

Yes _______ No___X____

Petrobras informs about the Chairman of the Boardof Directors

—

Rio de Janeiro, August 20, 2025 –Petróleo Brasileiro S.A. – Petrobras, following up on the statement disclosed on December 16, 2024, announces that ithas received today the resignation, effective immediately, of the Chairman of the company's Board of Directors, Mr. Pietro Adamo SampaioMendes, from his positions as Chairman and member of the Board of Directors due to new professional challenges.

Upon his resignation, Mr. Pietro AdamoSampaio Mendes expressed his gratitude to his fellow Board members, the members of the Executive Board led by CEO Magda Chambriard, andPetrobras' teams for their collaboration during his tenure as Chairman of the Board. He also wished everyone success in the journey ahead.

In accordance with Paragraph 2 of Article18 of the company’s Bylaws, the Board of Directors itself may elect a replacement for the Chairman in the event of a vacancy. Thiselection will remain valid until the next General Shareholder Meeting.

Petrobras will keep the market informedon this matter.

www.petrobras.com.br/ir

For more information:

PETRÓLEO BRASILEIRO S.A. – PETROBRAS| Investor Relations

Email : petroinvest@petrobras.com.br/acionistas@petrobras.com.br

Av. Henrique Valadares, 28 – 9th floor –20231-030 – Rio de Janeiro, RJ.

This document may contain forecastswithin the meaning of Section 27A of the Securities Act of 1933, as amended (Securities Act), and Section 21E of the Securities TradingAct of 1934, as amended (Trading Act) that reflect the expectations of the Company's officers. The terms: "anticipates", "believes","expects", "predicts", "intends", "plans", "projects", "aims", "should,"and similar terms, aim to identify such forecasts, which evidently involve risks or uncertainties, predicted or not by the Company. Therefore,future results of the Company's operations may differ from current expectations, and the reader should not rely solely on the informationincluded herein.

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: August 20, 2025

PETRÓLEO BRASILEIRO S.A–PETROBRAS

By: /s/ Fernando Sabbi Melgarejo

______________________________

Fernando Sabbi Melgarejo

Chief Financial Officer and Investor RelationsOfficer