US STOCKS-Wall St keeps gains after Fed puts off rate hike
* Fed leaves rates unchanged, lowers economic growth forecast
* May producer price index up 0.4 pct vs est 0.3 pct
* Indexes up: Dow 0.26 pct, S&P 0.28 pct, Nasdaq 0.29 pct (Updates with post-Fed trading, comment from Yellen)
By Noel Randewich
June 15 (Reuters) - Wall Street maintained gains on Wednesday after the Federal Reserve left its key interest rate unchanged, soothing investors on edge about an impending vote in Britain on whether to leave the European Union.
The U.S. central bank also lowered its economic growth forecasts for 2016 and 2017 and signaled it still plans two rate increases this year.
While traders had not expected a rate increase this month by the Fed's Federal Open Market Committee, or FOMC, they have been eager for clues about the health of the economy and the trajectory of future hikes.
Investors have become more nervous ahead of a vote in Britain next week on whether to leave the European Union, with recent opinion polls indicating growing support for such a move.
The S&P 500 was poised to close higher following four straight sessions of losses caused in part by fears that a fractured EU could critically damage an already shaky global economy. Continuación...