U.S. stock index futures jumped at the start of electronic trading Sunday evening as investors bet that lawmakers in Washington were set to reach a deal on raising the nation's debt limit.

S&P 500 futures rose 17.6 points and were above 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 rose 154 points, and Nasdaq 100 futures gained 31.75 points.