The last time that VIX closed below 12.50 was August 10, 2015, when it closed at 12.23 and the S&P 500 closed at 2104.18. A little over two weeks later on August 25, the S&P 500 closed at 1867.61, for a drop of 11.24%. If you go back to May 21, when the VIX closed at 12.11, and the S&P hit its previous all-time high, once again, 11 days later the S&P closed down 2.42%.