Technology companies led the gains, echoing Tuesday's action, with Apple Inc., Google Inc. and Qualcomm Inc. rising at least 2 percent. Banks were also on a path similar to yesterday's with JPMorgan Chase & Co. and Citigroup Inc. increasing more than 1.5 percent. Cameron International Corp. soared 41 percent after agreeing to be bought by Schlumberger Ltd. in a $14.8 billion deal.

The Standard & Poor's 500 Index climbed 1.1 percent to 1,888.06 at 11:36 a.m. in New York, trimming an earlier 2.5 percent rise. The Dow Jones Industrial Average added 179.25 points, or 1.1 percent, to 15,845.69 after earlier rising more than 430 points. The Nasdaq Composite Index also gained 1.1 percent.  

"This type of short-term rally shouldn't be much surprise given recent weakness," said Chad Morganlander, a money manager at Stifel, Nicolaus & Co. in Florham Park, New Jersey, which oversees about $170 billion. "But nonetheless, investors are resetting their global growth expectations, and that's having a deleterious effect in the longer term. The acceleration of the situation has investors on edge."

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