Bill Gates says he plans to donate nearly all his wealth to the foundation he launched with his ex-wife, Melinda, to the extent that he will eventually no longer be among the world’s richest people.

The Microsoft co-founder said in a Twitter thread Wednesday that he plans “to give virtually all” his wealth to the Bill and Melinda Gates Foundation, and that he “will move down and eventually off of the list of the world’s richest people” in doing so.

Gates is currently the fourth-richest person in the world with an estimated net worth of $129 billion, according to Forbes, which keeps a running list. He is also considered the largest private owner of farmland in the U.S., holding upward of 260,000 acres in dozens of states.

In his social media posts, Gates also gave a shout-out to the third-richest person in the world, Berkshire Hathaway CEO Warren Buffett, for his own contributions to the Gates Foundation.