Lloyd Blankfein, chairman and chief executive officer of Goldman Sachs Group Inc., speaks at the CARE conference in Washington, D.C., U.S., on Wednesday, March 9, 2011. Blankfein agreed to be a prosecution witness in Galleon Group LLC co-founder Raj Rajaratnam's insider trading trial this week, said a person briefed on the matter. Photographer: Andrew Harrer/Bloomberg via Getty Images