Walmart Stores Is Working on a Rival to Amazon's Prime Service

Walmart (WMT) is working on a rival for Amazon's (AMZN) prime service. This is Walmart's latest attempt to stay competitive with the online retailer. Walmart says its program will cost $50 a year, lower than Amazon's $99 a dollar a year subscription. Puma Biotech's (PBYI) breast cancer drug showed it did improve survival for patients but only by 2.3 months. Investors thought it would perform better than that. The drug also had some undesirable side effects. Shares of Puma Biotech slid 25% in pre-market trading. Shake Shack (SHAK) crushed expectations in its first quarter earnings. Revenue was up 56% from the same quarter a year ago.