The continuation of Operation Twist "should put downward pressure on longer-term interest rates and help to make broader financial conditions more accommodative," the Federal Open Market Committee said in a statement.
The Standard & Poor's 500 dropped 0.17%, or 2.29 points, to 1,355.69. The Dow Jones Industrial Average declined by 0.10%, or 12.94 points, to 12,824.39. The Nasdaq Composite gained 0.02%, or 0.69 points, to 2,930.45.