The core e-commerce business has completely upended the retail industry, leading to weakness at companies ranging from Macy's Inc (NYSE: M ) to Foot Locker, Inc. (NYSE: FL ) to J C Penney Company Inc (NYSE: JCP ). Stocks of distributors like W W Grainger Inc (NYSE: GWW ) in the industrial space and Cardinal Health Inc (NYSE: CAH ) in the medical sector have been pressured by fears of Amazon's entry. The grocery sector still hasn't recovered from Amazon's purchase of Whole Foods, even though WFM has roughly 3% market share.