U.S. stocks maintained gains on Wednesday after the Federal Reserve said it would leave interest rates unchanged and reaffirmed its promise to keep rates low for an extended period.

The Fed voted unanimously to keep benchmark borrowing costs near historic lows in a range of zero to 0.25 percent and reminded markets it will let most of the special liquidity facilities expire by early next year.

Their primary focus is still the labor market and they're not at all concerned about inflation, said Dan Cook, senior market analyst at IG Markets in Chicago.

By putting a firm date on the end of some of these facilities -- which will be coming up quickly -- that might put a bit of pressure on the stock market in the first part of 2010. Banks aren't going to have the liquidity to deal.

Banking stocks also held their gains, with the S&P Financial Index <.GSPF> up 1.1 percent. JP Morgan , up 1.9 percent at $41.65, contributed the most to the Dow's gain.

The Dow Jones industrial average <.DJI> advanced 16.55 points, or 0.16 percent, to 10,468.55. The Standard & Poor's 500 Index <.SPX> rose 4.94 points, or 0.45 percent, to 1,112.87. The Nasdaq Composite Index <.IXIC> gained 11.31 points, or 0.51 percent, to 2,212.36.

(Additional reporting by Leah Schnurr; Editing by Jan Paschal)