Futures snapshot at 07:05 p.m. EDT:
* S&P 500 e-minis fell by 123.5 points or 4.17 percent, with 127,430 contracts changing hands.
* Nasdaq 100 e-minis fell by 329 points or 3.87 percent, on volume of 30,111 contracts.
* Dow e-minis fell by 989 points or 3.83 percent, with 13,943 contracts changing hands.
* Prices for benchmark 10-year note futures rose more than a point.