The New York Stock Exchange and NYSE Amex Cash Markets invoked Rule 48 on Thursday after European leaders agreed to boost the region's bailout fund and struck a deal with private banks and insurers to accept 50 percent losses on Greek bonds.
Rule 48 is invoked to speed up and smooth trading at the market open when exceptionally high volatility is expected.
S&P 500 futures rose 34.4 points and were well 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 soared 258 points, and Nasdaq 100 futures jumped 56.25 points.
(Reporting by Chuck Mikolajczak; editing by Jeffrey Benkoe)