Brazil’s Senate yesterday opened an official investigation of Petroleo Brasileiro Petrobras SA (ADR) (NYSE:PBR) 2006 acquisition of a U.S. refinery for which opposition senators say the company overpaid.The panel’s first action was to vote on a list of more than 70 people who will be called to testify; current CEO Maria das Graças Silva Foster and the CEO before Foster, José Sergio Gabrielli, are expected … Continue reading Basic Material Active Stocks: Petroleo Brasileiro Petrobras (NYSE:PBR), AK Steel Holding (NYSE:AKS), Chesapeake Energy Corporation (NYSE:CHK), Alpha Natural Resources (NYSE:ANR)