Last year, the S&P 500 fell 4.8% in September for its first loss in eight months. At the time, worries were brewing about when the Federal Reserve would take its foot off the economic stimulus accelerator.
It's not always so. Two years earlier, a solid September gain helped to virtually reverse an August swoon. And in 2010, when the economy was climbing back from the Great Recession, September was the best month of the year for stocks.
This year's September has plenty of big events circled on the calendar that could yield more big swings for a market that's already been beset by them. Chief among them is the Federal Reserve's meeting on interest-rate policy Sept. 20-21. It's almost certain to raise its benchmark short-term rate for the fifth time this year. The only question is by how much.
Several reports on the economy before that crucial meeting could alter the Fed's thinking ahead of that meeting, including August hiring data due Friday and a report on inflation due Sept. 13.