September has always had a bad reputation in markets. Traders emerge from their beach houses and mountain cabins only to discover that the mood has shifted: summer's warmth does not extend to equities. Since 2000, the S&P 500 has lost, on average, 1.5% during this month. Like clockwork, the season of pumpkin spice seems to coincide with a certain queasiness about corporate earnings and Federal Reserve policy.
