From the abstract:
In the years since 1980, there has been a well-documented upward redistribution of income. While there are some differences by methodology and the precise years chosen, the top one percent of households have seen their income share roughly double from 10 percent in 1980 to 20 percent in the second decade of the 21st century. As a result of this upward redistribution, most workers have seen little improvement in living standards from the productivity gains over this period.
This paper argues that the bulk of this upward redistribution comes from the growth of rents in the economy in four major areas: patent and copyright protection, the financial sector, the pay of CEOs and other top executives, and protectionist measures that have boosted the pay of doctors and other highly educated professionals. The argument on rents is important because, if correct, it means that there is nothing intrinsic to capitalism that led to this rapid rise in inequality, as for example argued by Thomas Piketty.