U.S. stocks ended lower, after swinging between gains and losses, as the Federal Reserve’s decision to keep interest rates near zero percent raised questions about the strength of the global economy.

The Fed kept its policy interest rate unchanged, showing reluctance to end an era of record monetary stimulus in a time of market turmoil, rising international risks and slow inflation at home. Stocks erased an advance after Chair Janet Yellen indicated that risks in the global economy overshadowed signs of strength in America while inflation remained stubbornly low.

The Standard & Poor’s 500 Index fell 0.3 percent to 1,990.19 at 4 p.m. in New York, reversing a gain of as much as 1.3 percent. Stocks most sensitive to interest rates had the largest moves, with utilities and real-estate companies advancing more than 0.9 percent while banks lost 2.4 percent.

The decision to stand pat on rates keeps a pillar of the bull market in place, as record-low borrowing costs have helped propel stocks higher by nearly 200 percent in the past 6 1/2 years.

It also amplifies uncertainty about the strength of the American economy at a time financial markets have been roiled by concern that a slowdown in China will spread. The S&P 500 had fallen 3.1 percent this year through Wednesday after three years of double-digit gains.

Source: Bloomberg