Brazil's competition watchdog has requested a "quantitative study" of Ipiranga's US$600mn takeover of local fuel distributor Alesat.
The country's consumer protection agency has detected the sale of incomplete liters at more than 30 gas stations in Guerrero state.
State oil company Ecopetrol said it has taken advantage of new, high-demand markets.
Paulo Valois, a Brazilian lawyer who specializes in the oil and gas industry, spoke to BNamericas about the recently approved bill that lifts restrictions on private operators in pre-salt areas, which could lead to a "return to a positive business environment."
Production of polyethylene (PE) in Latin America is expected to increase next year.
The public interest suit claims Brazil's state-run oil company is selling the assets without a competitive bidding process.