NEW YORK, June 20 (Reuters) - The S&P 500 and Dow ended down slightly on Wednesday after the Federal Reserve acted to aid the economy with measures that were largely in line with what the market expected, but no more.

Based on the latest available data, the Dow Jones industrial average was down 13.09 points, or 0.10 percent, at 12,824.24. The Standard & Poor's 500 Index was down 2.28 points, or 0.17 percent, at 1,355.70. The Nasdaq Composite Index was up 0.69 point, or 0.02 percent, at 2,930.45.