Shares of Petrobras (NYSE:PBR), Brazil's state-run oil giant, tumbled 8% at market opening on Wednesday following the announcement that CEO Jean Paul Prates would be stepping down.

He is set to be replaced by a former regulator whose views align more closely with those of President Luiz Inacio Lula da Silva.

Industry experts have voiced concerns over this leadership change.

Prates was regarded as a stabilizing force, adept at balancing market expectations for disciplined capital spending and robust dividends with political pressures to keep fuel prices stable and boost job creation in key sectors.

Prates' departure marks him as the fourth CEO to be ousted from Petrobras in approximately four years, primarily due to political motivations.

This pattern of dismissals has reignited concerns about the potential use of Petrobras as an instrument to stimulate the Brazilian economy to the detriment of minority shareholders.