America’s biggest companies are grabbing a swelling share of revenues while workers suffer from pedestrian wage growth, teeing up an intensifying debate over whether public policy needs to respond.

So-called  superstar companies are becoming increasingly powerful in their sectors, allowing some to widen the mark-ups they charge on products and services. As these highly profitable businesses become more dominant, workers are capturing a smaller slice of the economic pie, some analysts say, contributing to income inequality. 

Democratic party politicians and progressive think-tanks have latched on to the phenomenon: Elizabeth Warren, the Massachusetts senator, has urged that antitrust authorities sharpen their teeth and claims that “competition is dying” in America.