U.S. stocks closed mixed in choppy trade Monday, the first day of the month. In U.S. economic news, the Institute for Supply Management said that its manufacturing index came in at 52.6. Any number above 50 indicates expansion. The dollar rose slightly against a basket of currencies. Light sweet crude oil for September delivery fell 3.7 percent to $40.06 a barrel on the New York Mercantile Exchange, while gold futures added $2.10 to $1,359.60 an ounce. The Dow Jones industrial average dropped 27.46, or 0.15 percent, to 18,404.78. The broader Standard & Poor's 500 index declined 2.76, or 0.13 percent, to 2,170.84. The technology-heavy Nasdaq composite index rose 22.07, or 0.43 percent, to 5,184.20.