The chief executive officer of Petrobras resigned in the wake of a fuel price increase that angered the president.

He resigned in a statement on Monday. While the state-owned oil firm went through the formal procedures for appointing the next CEO, Bolsonaro was still in the role.

Petrobras has underperformed during this year's oil rally

The company, which recently lost the title of Latin America's most valuable publicly-traded firm to miner Vale SA, lost about 35 billion reais ($8.6 billion) in market value since Friday, when it raised domestic fuel prices. In Sao Paolo, preferred shares fell as much as 5.1%.

Analysts led by Pedro Soares wrote in a note that they don't expect noise to go away until October. Between now and the election day, there will be major government opposition to any future fuel price increases.

Petrobras Gas Stations And Headquarters Ahead Of Earnings As Privatization Looms
A Brazilian flag flies outside Petrobras’s headquarters in Rio de Janeiro

The Congress will investigate Petrobras.

Brazil's president, who is seeking re-election in October, has been publicly bashing Petrobras for what he calls "abusive profits" and has sacked three of its chief executive officers. Voters are dissatisfied with the price of gas and inflation as a whole.

The congress supports a probe into the state-controlled company and its pricing policy, according to the congressman. The speaker of the lower house is threatening to impose taxes on the company's record profits.

Martha viotti Beck assisted.

(Updates with market reaction in paragraphs 3-4.)