A late push was enough to nudge the Standard & Poor’s 500 index into positive territory by half a point Wednesday, as investors bought up oil refiners, mining companies and technology stocks. Refiners such as Tesoro Corp. led the gains.
Stocks were down for most of the day, but began to crawl back in the afternoon. The S&P 500 index added 0.57 points, or 0.03 percent, to close at 1,868.20. The Nasdaq composite also rebounded. It gained 16.14 points, or 0.4 percent, to 4,323.33. Only the Dow Jones industrial average ended lower. It fell 11.17 points, or 0.1 percent, to 16,340.08.
Investors are worried about a drop in China’s exports, raising concerns that the second-largest economy is slowing.