Wall Street fell for a fifth straight session on Wednesday after the Federal Reserve left interest rates unchanged and investors stewed over an impending vote in Britain on whether to leave the European Union.
Major U.S. stock indexes spent most of the day with gains but abruptly fell late in the session, bringing the S&P 500's loss in the past week to 2.2 percent, in large part because of fears that a fractured EU could critically damage an already feeble global economy.
It was the S&P 500's longest losing streak since the five-day decline that culminated in its 2016 low on Feb. 11.
While the U.S. central bank put off an immediate rate hike, it lowered its economic growth forecast and signaled it still plans two rate increases this year.
Traders had not expected a rate increase this month by the Fed's Federal Open Market Committee, or FOMC, but 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 EU, with recent opinion polls indicating growing support for such a move.
"It is certainly one of the uncertainties that we discussed and that factored into today's decision," Fed Chair Janet Yellen said at a news conference.
The CBOE market volatility index .VIX, Wall Street's "fear gauge", fell 1.8 percent for the day but was still at elevated levels not seen in over three months.
"This is an FOMC announcement that really speaks to a global weakness and the bottom line is it underscores the fact the U.S. is not an island and the global markets and economy are more interconnected than they have ever been," said Peter Kenny, Senior Market Strategist at Global Markets Advisory Group in Berkeley Heights, New Jersey.
The Dow Jones industrial average .DJI lost 0.2 percent to end at 17,640.17 and the S&P 500 .SPX fell 0.18 percent to 2,071.50.
The Nasdaq Composite .IXIC dropped 0.18 percent to 4,834.93.
About 6.8 billion shares changed hands on U.S. exchanges, about average over the past 20 trading days, according to Thomson Reuters data.
Six of the 10 major S&P sectors dipped, led lower by the utilities index .SPLRCU, down 0.71 percent.
Chipmaker Intel (INTC.O) fell 1.65 percent and provided the biggest drag on the S&P 500. So far in 2016, the S&P 500 is up 1 percent.
Advancing issues outnumbered decliners on the NYSE by 1,833 to 1,189. On the Nasdaq, 1,536 issues rose and 1,271 fell.
The S&P 500 index showed 12 new 52-week highs and one new low, while the Nasdaq recorded 38 new highs and 37 new lows.
(Additional reporting by Yashaswini Swamynathan in Bengaluru; Editing by James Dalgleish)