Stocks Turn Lower After Housing News By: CNBC.com News July 20, 2011 at 10:09 AM EDT Stocks turned negative Wednesday, following a sharp rally in the previous session, after existing home sales tumbled unexpectedly to a seven-month low.� Read More >> Related Stocks: Abbott Laboratories American Express Apple BlackRock Boeing Co Caterpillar Clorox Co E Trade Financial Ecolab Intel Corp JPMorgan Chase & Co Johnson Controls Qualcomm, Inc. U.S. Bancorp United Technologies eBay