“There’s also statistical evidence for a rising role of monopoly power. Recent work by Jason Furman, chairman of the Council of Economic Advisers, and Peter Orszag, former head of the Office of Management and Budget, shows a rising number of firms earning “super-normal” returns—that is, they have persistently high profit rates that don’t seem to be diminished by competition.5”

Krugman, Paul, ‘Challenging the Oligarchy,’ a review of Robert B. Reich’s, Saving Capitalism: For the Many, Not the Few, (Knopf, 2016), in The New York Review, December 17, 2015, pp: 16-20.