The stock market’s so-called fear gauge shot up by nearly 10% Thursday as equities traded lower before Federal Reserve Chairman Ben Bernanke’s highly anticipated speech in Jackson Hole.

Volatility-linked exchange traded funds tracked the CBOE Volatility Index higher. These products, which include iPath S&P 500 VIX Short-Term Futures ETN (NYSEArca: VXX) and VelocityShares Daily 2X VIX Short-Term ETN (NYSEArca: TVIX), follow VIX futures rather than the spot price. The VIX tends to rise when stocks tank.

The two exchange traded notes climbed Thursday morning while stocks pulled back on worries Bernanke may not announce additional stimulus for the economy, while European markets were also shaky.

However, the volatility ETNs have seen outflows this week as they pull back from their recent highs. [VIX ETFs Broadcast Lingering Market Volatility]