“About 10 percent of the S&P 500 is energy and commodity related, and it is a barometer for global economy. When you see such a plunge, it worries investors,” Art Hogan, chief market strategist at Wunderlich Securities, told Reuters. “Until the oil market finds a support level, the market will remain unsettled.”

Moreover, traders remain skittish ahead of the Federal Reserve meeting next week. Many anticipate the Federal Open Market Committee will announce the start of its first rate hike in almost a decade on December 16.

iPath S&P 500 VIX Short Term Futures ETN

For more information on the CBOE Volatility Index, visit our VIX category.

Max Chen contributed to this article.