Stocks plunged worldwide Thursday as more signs of economic weakness revived investors' fears of another recession. The Dow Jones industrial average fell 400 points in a return to the wild swings in the market last week.

The Dow Jones industrial average notched a three-day win streak Monday for the first time in six weeks. A $19 billion corporate buying spree and encouraging economic news from Japan sent the Dow up 213 points and erased its losses from last week.

So much for the Fed-inspired rally. Investors' attention has turned back to the weak economy and that's bad news for stocks.

Bargain hunters helped push the Dow back above 11,000 briefly Tuesday.

The U.S. stock market joined a sell-off around the world Monday in the first trading since Standard & Poor's downgraded American debt and gave investors another reason to be anxious.