NEW YORK, March 4 (Xinhua) -- Wall Street rebounded from a sharp plunge Tuesday as Ambac rumors, and comments from Amazon and Cisco, encouraged bargain hunting.

    Earlier Tuesday, the market plunged after Merrill Lynch cut the Citigroup's earnings estimates, because it believes the bank could write down another 18 billion U.S. dollars of debt tied to souring mortgages.

    Intel trimmed its gross-margin outlook for the current quarter due to lower NAND flash-memory chip prices than expected, which intensified concerns about the technology sector.

    Ahead of Tuesday's opening bell, Federal Reserve Chairman Ben Bernanke delivered a speech on the subprime crisis and preventing foreclosures. He called for additional action to prevent more distressed homeowners from falling into foreclosure.

    In the afternoon, the financial sector rebounded after CNBC reported that a plan to save the bond insurer Ambac Financial is advancing nicely.

    Technology stocks rebounded, too, after a Dow Jones Newswires report that Cisco CEO John Chambers said he is "even more comfortable" with the long-term growth targets the company has outlined, and after Amazon.com's chief financial officer reiterated the online retailer's 2008 revenue forecast.

    The Dow Jones industrial average fell 45.10, or 0.37 percent, to 12,213.80, after tumbling more than 200 points earlier in the day.

    The Standard & Poor's 500 index fell 4.59, or 0.34 percent, to 1,326.75, while the Nasdaq composite index rose 1.68, or 0.07 percent, to 2,260.28.