US stocks edged higher on Wednesday after Federal Reserve Chairman Ben Bernanke said the timeline for winding down the US central bank's stimulus programme was not set in stone. The Dow Jones industrial average was up 18.67 points, or 0.12 percent, to end unofficially at 15,470.52. The Standard & Poor's 500 Index was up 4.65 points, or 0.27 percent, to finish unofficially at 1,680.91. The Nasdaq Composite Index was up 11.50 points, or 0.32 percent, to close unofficially at 3,610.00.