Most private equity firms are paid on the 2-and-20 model: a 2 percent annual fixed fee on all the money it invests and 20 percent of all profits above a certain threshold. The United States taxes money made from investments—so-called capital gains—at a lower level than money made through ordinary labor, whether at a factory or in an office. The distinction is ambiguous and unfair, but even more so, private equity firms have convinced the IRS that their 20 percent income should be taxed at the lower capital gains rate than at the higher ordinary income rate.
Brendan Ballou in Plunder