LONDON (MarketWatch) -- S&P 500 futures reached limit down in electronic trade on Friday, meaning that they can't fall beyond 60 points until the pits open at 9:30 a.m. Eastern. The contract, however, still can be traded. The limit on Nasdaq 100 futures is 85 points and the limit on Dow Jones Industrial Average futures is 550 points; both contracts were trading just above those thresholds. (Corrects time when pits open.)