Wall Street Journal: After dipping its toes into brick-and-mortar retail last year by opening its first physical bookstore, Amazon could be diving into the deep end. The company plans as many as 400 bookstores, Sandeep Mathrani, CEO of mall operator General Growth Properties , said on an earnings call. “You’ve got Amazon opening brick-and-mortar bookstores and their goal is to open, as I understand, 300 to 400.”