Stock futures declined before the opening bell Monday after the U.S. credit rating was downgraded by Moody's Ratings on Friday. As of 8:30 a.m. EST, S&P 500 futures had shed 65 points, or 1.1%, while Dow Jones Industrial Average futures declined 252 points or 0.

Strategists warned the move, announced after the market close on Friday, could spark some near-term selling in stocks and Treasurys.

The stock market opened with losses Monday as trading began for the first time since the U.S. government suffered a significant hit to its creditworthiness. The Dow Jones Industrial Average,