U.S. Stocks Tumble After S&P Downgrade

U.S. stocks are tumbling amid a rout in global markets after Standard & Poor's downgraded the U.S. credit rating for the first time.

S&P cut the long-term debt rating for the U.S. by one notch late Friday. The downgrade wasn't unexpected, but it comes when investors are already nervous about a weak U.S. economy, European debt problems and Japan's recovery from its March earthquake.

At the opening of trading, the Dow Jones industrial average is down 192, or 1.7 percent, to 11,252. The S&P 500 is down 23, or 2 percent to 1,176. The Nasdaq is down 64, or 2.5 percent, to 2,468.

Prices for Treasurys are rising because they're still seen as one of the few safe investments. Gold topped $1,700 per ounce for the first time.