Futures snapshot at 8:59 a.m. EDT:

* S&P 500 e-minis were down 76 points, or 3.85 percent, with 1,153,980 contracts changing hands.

* Nasdaq 100 e-minis were down 208.5 points, or 4.96 percent, in volume of 136,101 contracts.

* Dow e-minis <1YMc1> were down 666 points, or 4.04 percent, with 141,464 contracts changing hands.