A co-founder of Facebook is donating $20 million of his estimated $10 billion dollar fortune to help defeat Republican candidate Donald Trump in the 2016 presidential election.

The pledge came as a surprise because he has never been active in politics before.

Dustin Moskovitz announced early Friday that he and his wife would make a historically large donation to a half-dozen Democratic groups as reported by CNN. The donations would make Moskovitz the third most generous donor in the 2016 campaign.

Moskovitz and his wife Cari Tuna wrote in a post on Medium:

This decision was not easy, particularly because we have reservations about anyone using large amounts of money to influence elections. We hope these efforts make it a little more likely that Secretary Clinton is able to pursue the agenda she’s outlined, and serve as a signal to the Republican Party that by running this kind of campaign — one built on fear and hostility — and supporting this kind of candidate, they compel people to act in response.

Moskovitz stated $5 million would go to a super PAC run by the League of Conservation Voters and another $5 million to For Our Future PAC.

Other donations would be split between a joint fundraising committee for Hillary Clinton; the Democratic Congressional Campaign Comittee; the Democratic Senatorial Campaign Committee; a political arm of MoveOn.Org; Color of Change PAC; and several other nonpartisan voter registration and GOTV efforts.

This article is republished with permission from our friends at the Shark Tank.