The Dow Jones Industrial Average posted its largest point plummet since March 2001 Thursday, plunging 438 points in afternoon trading, a 3.2 percent drop economists attribute primarily to credit-market worries.

"There is a terrible scare about the consequences about the sub-prime loan crisis," said  Peter Morici, an economist  at the University of Maryland's Robert H. Smith School of Business.  "I think it's overplayed and the market is overreacting."

Though the Dow recovered to close at 13,474, a net drop for the day of 311 points, or 2.26 percent, the   credit concerns reverberated globally.  Major stock indexes in Argentina, Brazil, Mexico, Turkey and Sweden experienced a 3 percent drop, Bloomberg News reported Thursday.

Wall Street pointed to higher oil prices and the housing slump as reasons alongside the credit-market scare   for the  tumble, but expressed optimism about a market rebound.

"I really believe that this market maybe bottoms today or tomorrow," Matthew McCall, president of Penn Financial Group, told CNBC Thursday, "but there's going to be a great buying opportunity on this volatility in the coming week."