The private-equity industry is pouring millions of dollars into the 2020 elections, with some donors hoping to prevent full Democratic control of Capitol Hill and the potential for tighter oversight of their sector.

Employees of private-equity firms and other investment firms, not including hedge funds, spent $91.7m on 2020 congressional races and presidential campaigns through July 21, according to the Center for Responsive Politics, a nonprofit group that researches money in politics.