Insiders have been pulling out of stocks just as small investors are getting in.
Selling by corporate executives has surged recently as the Dow Jones Industrial Average hit 14,000 and retail investors flooded into stocks. The amount of insider selling has usually preceded market selloffs.
There have been more than nine insider sales for every one buy over the past week among NYSE stocks, according to Vickers. The last time executives sold their company's stock this aggressively was in early 2012, just before the S&P 500 went on to correct by 10 percent to its low for the year.
"Insiders know more than the vast majority of market participants," said Enis Taner, global macro editor for RiskReversal.com. "And they're usually right over a long period of time."
