WASHINGTON -- The main arm of the political network operated by billionaire conservatives Charles and David Koch raised $126 million in 2014 and distributed millions to more than 20 other groups active in last year's midterm elections.

According to an annual tax filing posted Tuesday on the Freedom Partners Chamber of Commerce website, the nonprofit group gave $87.6 million in grants and contributions to outside groups. It spent $28.5 million on its own activities and paid $13.3 million in salaries for its well-compensated managers.

Freedom Partners Chamber of Commerce, which is registered as a 501(c)(6) trade association, serves mainly as a fundraising portal to distribute money from its 200-plus donors to conservative political groups. As a nonprofit, it's not required to -- and doesn't -- disclose its donors.