Wall Street stocks closed lower on Monday with the benchmark index Standard & Poor's 500 dropping for the third successive session amid speculation that the Federal Reserve may trim its bond purchases further. The Dow Jones industrial average slid 0.26% to 15,837.88, the S&P 500 Index lost 0.49% to 1,781.56 and the Nasdaq Composite index fell 1.08% to 4,083.61.