Petrobras reached a record market capitalization of R$ 700.08 billion (around $128 billion) at the close of trading on the B3 stock exchange on Friday (Oct. 2), driven by a second deepwater oil discovery in the Foz do Amazonas basin. In a single trading session, the state-run company added R$ 20.9 billion to its market value, with preferred shares climbing 2.81% and common voting shares rising 3.25%, according to corporate filings and exchange data.
The discovery occurred at the Morpho exploratory well in the FZA-M-59 block, located 175 kilometers (109 miles) off the coast of the northern state of Amapá at a water depth of 2,886 meters. Petrobras had registered initial signs of crude at the site in mid-August, and deeper drilling confirmed additional oil layers. Petrobras CEO Magda Chambriard told reporters that drilling operations have finished and technicians are carrying out final tests, with work on the well scheduled for completion by late October.
Developing the Equatorial Margin addresses a structural shift in Brazil's energy supply chain. Official estimates from the National Agency of Petroleum, Natural Gas and Biofuels (ANP) project that current pre-salt fields off the southeastern coast will begin a natural output decline within the next decade. A study by the state-run Energy Research Office (EPE) estimates the recoverable resources of the Foz do Amazonas basin could reach 10 billion barrels of oil equivalent, providing crude to feed domestic refineries and generating tax revenues for northern states.
The project continues to face legal pushback. Late last month, the Federal Public Prosecutor's Office asked a federal appeals court to suspend the exploratory environmental permit issued by the environmental agency Ibama in October 2025. Prosecutors argue that the project lacked required prior consultations with local indigenous and traditional fishing communities, and cited potential operational hazards in the sensitive Amazon marine environment.
On financial markets, the milestone consolidates strong capital returns relative to global competitors. From January through September 2026, Petrobras delivered a total shareholder return of roughly 185% in dollar terms, surpassing peers such as Chevron (138%) and ExxonMobil (138%), according to company data. For industrial producers and agribusiness freight operators, expanding domestic reserves offers long-term fuel supply security, while retail consumers will see pump prices determined by commercial extraction costs and global crude benchmarks.