Wall Street ends lower after Fed keeps rates unchanged

Wall Street ended lower on Wednesday after the Federal Reserve left interest rates unchanged but opened the door to a possible rate increase later this year.

The S&P 500 recently traded at about 17.2 times expected earnings, up from about 16.5 at the start of the year, according to Thomson Reuters Datastream.

In a volatile session, the Dow Jones industrial average finished down a marginal 0.01 percent at 18,472.17 points and the S&P 500 ended down 0.12 percent at 2,166.58.

The Nasdaq Composite added 0.58 percent to 5,139.81.