The Ibovespa gained about 0.5% to trade above 171,000 on Thursday, supported by strength in energy stocks.
Petrobras rose nearly 1% as markets reassessed the outlook for global oil supply following renewed US-Iran hostilities.
Banking shares also advanced, with Itaú and Bradesco gaining more than 0.5%.
Vale rebounded 0.5% despite lower iron ore prices.
Other notable gainers included Ambev and Embraer, both up more than 0.5%.
Meanwhile, US Trade Representative Jamieson Greer said a decision on US tariffs on Brazilian imports would be made very soon, although negotiations between the two countries remain far apart.