Amazon Soars on Surprise Profit; Stocks Are Modestly Lower

Amazon (AMZN) blew past earnings estimates, posting a surprise profit, thanks to strong growth in Prime memberships. The ensuing rally pushed Amazon's market cap higher than brick-and-mortar retailer Walmart (WMT). Amazon's surge was countered by Biogen (BIIB) which sank after lowering full-year guidance based on weaker demand for its multiple sclerosis drugs. Starbucks (SBUX) was higher after edging past earnings estimates and reporting a nearly 20% surge in sales. Global traffic increased 7%. It's been a taxing week for Wall Street as industry bellwethers the likes of Apple (AAPL) and Caterpillar (CAT) fell short of estimates. Broad declines pushed benchmark indexes into the red for the day and facing a weekly loss of more than 1% each.