U.S. stocks fell, erasing an early rally, as investors sold some of the month’s best-performing shares on the final day of the market’s biggest September rally since 1939. Caterpillar Inc., which has rallied more than 20 percent in September for the top gain in the Dow Jones Industrial Average, fell 2 percent to lead the 30-stock gauge lower today. Apple Inc., up 17 percent this month, slumped 1.7 percent and was the biggest drag on the Standard & Poor’s 500 Index. Benchmark indexes erased an early rally triggered by better-than-estimated reports on the economy. The S&P 500 slipped 0.3 percent to 1,141 at 11:43 a.m. in New York, trimming its monthly advance to 8.8 percent and its third-quarter gain to less than 11 percent. Technology and industrial companies, up more than 11 percent in September for the best gains among 10 groups, were the biggest drags on the S&P 500. The Dow slipped 44.35 points, or 0.4 percent, to 10,790.93. “Things were due for a pause, this being the last day of the quarter,” said Michael James, a managing director at Wedbush Morgan Securities in Los Angeles. “Nothing goes up in a straight line,” he said. “We’ve had a hard time making an attempt at higher highs. You’re seeing traders exit positions and lock in gains for the quarter.” To contact the reporter on this story: Inyoung Hwang in New York at ihwang7@bloomberg.net. To contact the editor responsible for this story: Nick Baker at nbaker7@bloomberg.net

Source