Attempts to monopolize an industry by purchasing (or eliminating) potential competitors can be a violation of antitrust law in the U.S.When companies purchase or develop a wider portfolio of companies across a range of industries (Amazon owns Zappos, Twitch, Whole Foods, Audible, Ring, and PillPack, for example), is there a similar potential for inefficiency? How is it similar to or different from a company that monopolizes a single industry?