Charles Koch donated $500K to Ryan days after GOP tax plan passed

GOP mega-donor Charles Koch and his wife donated around $500,000 to Speaker Paul RyanPaul Davis RyanGOP leaders pitch children's health funding in plan to avert shutdown Lawmakers see shutdown’s odds rising Fix what we’ve got and make Medicare right this year MORE’s (R-Wis.) joint fundraising committee, just days after the GOP tax plan was passed.

Koch made the donation 13 days after the plan was passed, which lowers the corporate tax rate and cuts estate taxes, HuffPost reported.

He and his wife also gave $237,000 each to the National Republican Congressional Committee on the same day, according to HuffPost.

Koch and his brother David Koch were both major advocates for the tax plan, pouring millions of dollars into efforts to get the legislation passed.

The pair is also planning on spending millions more on a public relations campaign for the plan, according to The Wall Street Journal.

Politico reported last year that Ryan isn't planning on running for another term, but Ryan has denied the report.