US stocks open mildly lower; housing data in focus By: CNBC.com News May 21, 2015 at 09:30 AM EDT U.S. stocks opened mildly lower on Thursday as investors awaited existing home sales, amid other data reports. Read More >> Related Stocks: Best Buy Campbell Soup Footlocker Inc Gap Hewlett-Packard Intuit Marvell Technology Inc Ross Stores Salesforce