Another giant merger involved retail pharmacies Walgreens Boots Alliance ( WBA 0.50% ) and Rite Aid. Walgreens is paying $17.2 billion in this all-cash transaction that will leave the company with $7.3 billion in debt. Previously, this space was dominated by the aforementioned two companies and CVS Health. As the market dwindles down to just two main players, it may raise flags with antitrust regulatory bodies, so we'll have to wait to see whether it gets the green light.