Those FANG stocks, which put the whole bull market on their back last year, are now one of the primary reasons equities are having one of the worst starts to a year ever.
All four FANG stocks are down more than 7 percent this year. Oil and China woes grab the headlines, but profit-taking by investors in these 2015 winners are one of the primary reasons the market is failing this year.
"It appears to me the FANGs have a cavity and we advised shorting the basket two weeks ago," BGC's senior macro strategist Steve Cortes said in an email. "When a market becomes this dependent on just a few names, it's generally unhealthy for overall risk."
And the stats show just how much FANG stocks dictated the direction of trading for the overall market the last 12 months.
Using Kensho, a quantitative tool used by hedge funds, CNBC Pro looked at what the market does when FANG stocks trade down on any given trading day in 2015 and 2016.