Stock index futures fell to session lows and pointed to a lower open on Tuesday as a spate of disappointing earnings raised concerns about the outlook for corporate profits.

S&P 500 futures dropped 7.00 points and were below fair value, a formula that evaluates pricing by taking into account interest rates, dividends and time to expiration on the contract. Dow Jones industrial average futures slid 71 points, and Nasdaq 100 futures fell 7.00 points.