Most investors understand that stocks produce superior long-term returns, but at the cost of higher volatility. Yet every time -- every single time -- there's even a hint of volatility, the same cry is heard from the investing public: "What is going on?!"
Nine times out of ten, the correct answer is the same: Nothing is going on. This is just what stocks do.
Since 1900 the S&P 500 (^GSPC) has returned about 6% per year, but the average difference between any year's highest close and lowest close is 23%. Remember this the next time someone tries to explain why the market is up or down by a few percentage points. They are basically trying to explain why summer came after spring.
Someone once asked J.P. Morgan what the market will do. "It will fluctuate," he allegedly said. Truer words have never been spoken.