Volatility-linked exchange traded funds rallied Thursday along with the CBOE Volatility Index as the Dow Jones Industrial average shed over 400 points.

Some traders are using volatility ETFs to manage the market’s swings and hedge equity portfolios. The VIX jumped nearly 30% to climb above 40.

Volatility-linked products follow VIX futures, rather than the spot price. [VIX ETF Surge Highlights Market Unease]

The iPath S&P 500 VIX Short-Term Futures ETN (NYSEArca: VXX) vaulted over 14%. Outstanding stock in the exchange traded note plunged 48% last week for the biggest drop in its 30-month history, report Jeff Kearns and Matt Robinson for Bloomberg.

Meanwhile, the VelocityShares Daily Inverse VIX Short Term ETN (NYSEArca: XIV) experienced record inflows, adding a 49.9 million shares and becoming the second-largest volatility-related ETN, according to the report.

Wild swings in the S&P 500 helped the VIX surge 50% to 48 on Aug. 8, the largest single-day gain since February 2007, followed by a 27% drop the next day, the second-largest single-day drop.

“It [the VIX]always reverts to the mean. That’s an easy call to make,” commented Randy Frederick, director of trading and derivatives for Charles Schwab. “The tough part is to say how quickly it’s going to do that. It always reverts back when you get extreme spikes, but the question is how extreme.”