Part of what’s moving traders is uncertainty about the Fed’s next moves. But a number of key factors around the world have investors bracing for more sharp peaks and deep valleys.

Two of the major stock indices closed at five-year highs today, while the CBOE Volatility Index drops to its lowest since April 2007.

So far this year, just three days have seen the S&P gain or lose more than one percent. So what happened to the markets' roller coaster ride of 2011?

In volatile times, traders become extra sensitive to news or rumors that could put them on the wrong side of a trade…even when the markets are closed for Christmas.

It’s been a year of historic volatility in the financial markets. We explore the short- and long-term reasons behind the volatility.