U.S. stock index futures fall, with Nasdaq 100 index futures giving back a 0.7% increase.

US stock index futures fell, with most turning lower. S&P 500 index futures are now down 0.02%, after briefly rising 0.4%; Nasdaq 100 index futures are now down 0.08%, after briefly rising 0.7%. Dow Jones index futures are now up 0.06%.