Federal Reserve Board Governor Kevin Warsh told participants at an industry conference that the Federal Reserve's bond-buying program likely will not do much to spur the economy. "I am less optimistic than some that additional asset purchases will have significant, durable benefits for the real economy," he said. The central bank recently announced plans to buy another $600 billion in Treasurys. "Expanding the Fed's balance sheet is not a free option. There are significant risks that bear careful monitoring," Mr. Warsh said.