UNITED STATES
SECURITIES AND EXCHANGE
COMMISSION
Washington, D.C.
20549
FORM 6-K
Report of Foreign Private
Issuer
Pursuant to Rule 13a-16 or 15d-16 of the
Securities Exchange
Act of 1934
For the month of
January, 2026
Commission File Number
1-15106
PETRÓLEO BRASILEIRO
S.A. – PETROBRAS
(Exact name of registrant
as specified in its charter)
Brazilian Petroleum
Corporation – PETROBRAS
(Translation of Registrant's
name into English)
Avenida Henrique Valadares, 28 – 9th floor
20231-030 – Rio de Janeiro, RJ
Federative Republic of Brazil
(Address of principal
executive office)
Indicate by check mark
whether the registrant files or will file annual reports under cover Form 20-F or Form 40-F.
Form 20-F ___X___ Form
40-F _______
Indicate by check mark
whether the registrant by furnishing the information contained in this Form is also thereby furnishing the information to the Commission
pursuant to Rule 12g3-2(b) under the Securities Exchange Act of 1934.
Yes _______ No___X____
Petrobras increases Proved Reserves in 2025
—
Rio de Janeiro, January 28, 2026 –Petróleo
Brasileiro S.A. – Petrobras discloses its proved reserves of oil, condensate and natural gas, according to SEC (U.S. Securities
and Exchange Commission) regulation, estimated at 12.1 billion barrels of oil equivalent (boe), as of December 31, 2025. Oil and condensate,
and natural gas correspond to 84% and 16% of this total, respectively.
In 2025, Petrobras followed the trajectory
of significant reserves addition (1.7 billion boe), maintaining focus on providing value for the society and shareholders, pursuing energy
security for the country's sustainable development and for a just energy transition. The reserve replacement rate (RRR) was 175%, even
after a record annual production in 2025. The proved reserves-to-production ratio (R/P) is 12.5 years.
The reserves addition occurred mainly
due to the outstanding performance of the assets, with emphasis on Búzios, Tupi, Itapu and Mero fields in Santos Basin, to the
progress in the development of Budião, Budião Noroeste and Budião Sudeste fields in the deep waters of Sergipe-Alagoas
Basin, and to new wells mainly in Búzios, Tupi, Marlim Sul and Jubarte fields in Santos and Campos basins. There were no relevant
changes related to the variation in the oil price, highlighting the resilience of our projects.
The evolution of proved reserves is shown
in the graph below.

Apparent differences in sums are due to rounding. [1] Does
not consider: (a) natural gas liquids, since the reserve is estimated at a reference point prior to gas processing, except in the United
States and Argentina; (b) volumes of injected gas; (c) production from extended well tests in exploration blocks; and (d) production in
Bolivia, since the Bolivian Constitution does not allow the registration of reserves by the company.
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.
Tel.: 55 (21) 3224-1510/9947
This document may contain forecasts
within the meaning of Section 27A of the Securities Act of 1933, as amended (Securities Act), and Section 21E of the Securities Trading
Act 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 information
included herein.
Considering the expected production for
the coming years, it is essential to continue investing in maximizing the recovery factor of already discovered assets, exploring new
frontiers and diversifying the exploratory portfolio in Brazil and abroad to replace oil and gas reserves.
Petrobras has submitted more than 90%
of its proved reserves, as defined under SEC regulations, to independent third-party evaluation. Currently, this evaluation is conducted
by DeGolyer and MacNaughton (D&M).
Petrobras also estimates reserves according
to the ANP/SPE (National Agency of Petroleum, Natural Gas and Biofuels / Society of Petroleum Engineers) definitions. As of December 31,
2025, the proved reserves according to these definitions reached 12.5 billion barrels of oil equivalent (boe). The differences between
reserves estimated by ANP/SPE definitions and those estimated using SEC regulation are mainly due to different economic assumptions and
the possibility, under ANP reserves regulations, of recognizing as reserves the volumes expected to be produced beyond the concession
term in Brazilian fields.
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.
Tel.: 55 (21) 3224-1510/9947
This document may contain forecasts
within the meaning of Section 27A of the Securities Act of 1933, as amended (Securities Act), and Section 21E of the Securities Trading
Act 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 information
included 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: January 28, 2026
PETRÓLEO BRASILEIRO S.A–PETROBRAS
By: /s/ Fernando Sabbi Melgarejo
______________________________
Fernando Sabbi Melgarejo
Chief Financial Officer and Investor Relations
Officer