UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 6-K PETRÓLEO BRASILEIRO S.A. – PETROBRAS Report of Foreign Private Issuer Pursuant to Rule 13a-16 or 15d-16 of the Securities Exchange Act of 1934 For the month of March, 2026 Commission File Number 1-15106 (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 r ...