ANOTHER SLIDE: Stocks gave up early gains to end lower for a second day Tuesday after an unexpected drop in sales of existing homes last month raised concerns about the economy's recovery.

　　LOSING ENERGY: The White House's pledge to appeal a judge's ruling overturning a ban on deepwater drilling in the Gulf of Mexico hurt energy stocks.

　　TECHNICAL PROBLEMS: The market's slide intensified in afternoon trading after the benchmark Standard & Poor's 500 index fell below 1,111, its average finish of the past 200 days. Traders see a move below this level as a predictor of more selling.