Mark Zuckerberg announced on Tuesday that he will put “99 percent” of his stock in Facebook toward “advancing human potential and promoting equality.”

Through an open letter to his daughter on Tuesday, the Facebook CEO, alongside his wife, Priscilla Chan, announced the formation of the Chan Zuckerberg Initiative: a philanthropic project which aims to bolster “human potential and promote equality in areas such as health, education, scientific research, and energy.”

The open letter outlines a few key areas: Improving medicine and fighting disease, promoting equality, and advancing human potential, which is defined as “pushing the boundaries on how great a human life can be.”

All of the funding for the Chan Zuckerberg Initiative will come from the Zuckerberg’s Facebook stock, which currently stands at $45 billion. But even after Zuckerberg gives up 99 percent of his stock, he’ll still be left with $450 million at its current valuation.

While the move is bold, the 31-year-old is far from a pioneer when it comes to America’s ultra-wealthy putting much of their fortunes toward the public good. He joins investor Warren Buffett and Microsoft founder Bill Gates in the endeavor. As Buffett has put it, his children will get “enough money so that they would feel they could do anything, but not so much that they could do nothing.”

Oh, and it’s official. Here’s his Form 8-K filing with the Securities and Exchange Commission, which reads:

“On December 1, 2015, our Founder, Chairman and CEO, Mark Zuckerberg, announced that, during his lifetime, he will gift or otherwise direct substantially all of his shares of Facebook stock, or the net after-tax proceeds from sales of such shares, to further the mission of advancing human potential and promoting equality by means of philanthropic, public advocacy, and other activities for the public good. For this purpose, Mr. Zuckerberg has established a new entity, the Chan Zuckerberg Initiative, LLC, and he will control the voting and disposition of any shares held by such entity. He has informed us that he plans to sell or gift no more than $1 billion of Facebook stock each year for the next three years and that he intends to retain his majority voting position in our stock for the foreseeable future. Any sale of shares by Mr. Zuckerberg will be conducted pursuant to a trading plan established pursuant to Rule 10b5-1 under the Securities Exchange Act of 1934, as amended (the “Exchange Act”). Sales and gifts of shares by Mr. Zuckerberg will be disclosed publicly in accordance with the rules established by the U.S. Securities and Exchange Commission under Section 16 of the Exchange Act. As of the date of this filing, Mr. Zuckerberg beneficially owns approximately 4 million shares of Class A common stock and approximately 419 million shares of Class B common stock.”