CITIGROUP : Stocks fall on Citigroup and profit worries

NEW YORK (Reuters) - U.S. stocks tumbled on Monday in the worst two-day slide in more than a month as investors worried about the outlook for embattled bank Citigroup and expectations mounted for dismal fourth-quarter earnings.

* The prospect of more financial sector losses stemming from the credit crisis pulled Citigroup stock down about 17 percent. The S&P Financial index <.GSPF> fell 5.7 percent.

* Alcoa Inc , which will start the earnings season with results after the closing bell, fell about 7 percent after being downgraded to "sell" by Deutsche Bank.

* The Dow Jones industrial average <.DJI> slipped 125.45 points, or 1.46 percent, at 8,473.73. The Standard & Poor's 500 Index <.SPX> shed 20.10 points, or 2.26 percent, at 870.25. The Nasdaq Composite Index <.IXIC> lost 32.80 points, or 2.09 percent, at 1,538.79.

(Reporting by Deepa Seetharaman; Editing by Leslie Adler)