U.S. markets closed in deep decline on Monday, with the Dow Jones industrial average dropping 634.76 points to 10809.85—its biggest one-day decline since the height of the financial crisis in December 2008. The S&P 500 Index tumbled more than 6 percent, while the Nasdaq dropped nearly 7 percent. U.S. stocks plummeted after gloomy openings in European and Asian markets, and investor anxiety increased with news that mortgage giants Fannie Mae and Freddie Mac had also been slammed with credit-rating downgrades. Financial stocks were among the hardest hit in the slump and fell as much as 10 percent during the final hours of trading. The value of gold, meanwhile, hit records as investors fled to safety.