“The new warning signs we detected yesterday came from the behavior in the Volatility Index, or VIX. The VIX is a measure of volatility expectations derived from trading in S&P 500 options. Typically, the VIX falls as the market rises. Yesterday, however, the VIX jumped more than 5% even though the S&P 500 hit a new high. How odd is that? Since 1998, it has only happened 10 other times.”

https://www.tumblr.com/jlfmi/102963367445/some-vexing-behavior-from-the-vix