Oil's Boom-to-Bust Swing Offers Traders More Volatility: Chart

As oil prices rattle around 12-year lows, traders have an old ally back: volatility.

The CBOE Crude Oil Volatility Index, which measures expectations of swings in prices, closed Monday near the highest level since March 2009. Greater volatility gives traders more opportunity to bet on price swings. West Texas Intermediate is falling a second day, extending its drop below $30 a barrel Tuesday after the biggest two-day rally in more than seven years.