Dow drops more than 100 points in open; Visa down 4% By: CNBC.com News July 25, 2014 at 09:35 AM EDT U.S. stocks opened lower despite positive data as weak Amazon earnings and concerns over continued unrest in Ukraine and Gaza weighed on markets. Read More >> Related Stocks: Amazon.com Baidu.com SP ADR Facebook Pandora Media Inc Sentinelone Inc Cl A Starbucks Corp Visa Xerox Corp