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.

Dow Futures fell by more than 300 points early on Monday, meanwhile 30-year U.S. Treasury bond yields rose past 5%.

U.S. stock index futures fell on Monday, while Treasury yields rose after ratings agency Moody's downgraded the country's sovereign rating by one notch, bringing forward concerns around the ballooning U.