While the S&P 500 index hit an all-time high last week, the VIX - the stock market's fear gauge - fell to near its lowest level since 2007. But that looks like it's now changing.
The VIX, formally known as the CBOE Volatility Index, jumped 17 percent yesterday. That's the steepest one-day increase we've seen in this measure since September.
Despite the upward movement, it's still historically fairly low. The moves in the VIX ended the day right around 12. A reading around 20 is typically considered a sign that fear has gripped the market. But a reading near 12, even though it's higher than recent readings, signals relative complacency.