Investors locked in profits from last week's rally to weigh down the markets during the midday. The Dow tumbled 117 points to 7900 while Nasdaq dropped 32 points to 1590.

On the upside

UBS upgraded Infineon Technologies (NYSE: IFX) on the expectation that the chipmaker will receive government backed debt financing.

Keefe Bruyette upgraded MF Global (NYSE: MF).

Shares of Dendreon (NYSE: DNDN) continued to soar in anticipation of the company's prostate cancer vaccine trial results.

On the downside

Credit Suisse analyst Steve Benyik downgraded SL Green Realty (NYSE: SLG) citing a weak liquidity outlook.

International Paper (NYSE: IP) announced the closure of a cardboard box plant in Kansas City, Kansas, a mill in Franklin, Virginina, a plant in Cedarburg, Wisconsin, and temorarily close its Ticonderoga, New York mill.

JPMorgan downgraded AXA (NYSE: AXA).

In the broad market, declining issues outpaced advancers by a margin of nearly 7 to 2 on the NYSE and by 3 to 1 on Nasdaq. The Russell 2000 which tracks small cap stocks tumbled 13 points to 443.