U.S. stocks sank early Monday, with the S&P 500 dropping 1% at the open, the Nasdaq sliding 1.3%, and the Dow Jones Industrial Average down 297 points, or about 0.6%. The VIX spiked 13% and gold pushed higher,

Moody's cut the United States' sovereign credit rating to "Aa1" from "Aaa" late on Friday owing to concerns about its ballooning $36-trillion debt, becoming the last of the three major credit rating agencies to downgrade the country. It had first given the U.S. its pristine "Aaa" rating in 1919.

U.S. stocks turned mostly higher despite Moody's trimming the US' credit rating. Treasury yields jump as investors demand more payout to hold US debt.