A handful of digital superpowers known as "hub firms" are capturing a disproportionate and expanding share of the global economy. These technology giants--Google, Facebook, and Amazon among them--have access to so much digital information about users, that they can compete in industries far outside the ones they start in. Marco Iansiti, Harvard Business School Professor and co-author of the Harvard Business Review article, "Managing our Hub Economy," says this trend threatens to exacerbate income inequality. Market share of technology MVP's including Apple, Amazon, Alphabet, Facebook and Microsoft is worth $3 trillion.