He can afford it

The BBC has an article about Mark Zuckerberg's latest:

Facebook's Mark Zuckerberg and his wife Priscilla Chan (photo above, left and right) say they will give away 99% of their shares in the company to good causes as they announce the birth of their daughter Max (photo above, center).
Zuckerberg made the announcement in a letter to Max on his Facebook page. He said they were donating their fortune to the Chan Zuckerberg Initiative to make the world a better place for Max to grow up in. The donation amounts to forty-five billion dollars at Facebook's current value. The shares will not be donated to charity immediately, but over the course of the lives of the couple.
Were Zuckerberg to give away 99% of his shares immediately, he would still possess hundreds of millions of dollars. Chan's worth has not been documented.
Max was born last week, although her birth was only made public since then.
In his letter, Zuckerberg said the aim of the Chan Zuckerberg Initiative is "to advance human potential and promote equality for all children in the next generation".
Its initial areas of focus will be personalized learning, curing disease, connecting people and building strong communities.
"Your mother and I don't yet have the words to describe the hope you give us for the future," Zuckerberg said at the start of his letter to Max. "You've already given us a reason to reflect on the world we hope you live in," it added. 

Dave Lee, North America Technology Reporter for the BBC, from San Francisco, California:
Billionaire investor Warren Buffet congratulated Zuckerberg and Chan, proclaiming that when it comes to giving away your fortune: "30 is the new 70". No longer should billionaires wait to die before handing over money to a different generation, Buffet said, in a gushing approval of Silicon Valley's newest and most influential power couple.
Everything Zuckerberg does is eyed with intense scrutiny, not least due to the nature of Facebook's business of making money from personal data.
But, while his previous charitable efforts have been criticized for being too focused on building Facebook's user base, this latest pledge appears to leave the Facebook business to one side. It's a continuation of what we've seen developing over the past six months, where Zuckerberg appears at ease hosting heads of state as he does in the company of his own development team.
The days of Zuckerberg being seen as a nerdy, awkward tech dork are well behind us.
His ambition now is clearly to be a significant figure on the global political stage. His letter highlighted the important role of technology in achieving the couple's goals of advancing human potential and equality."Many of the greatest opportunities for your generation will come from giving everyone access to the internet," Zuckerberg wrote to his daughter. He said more details about the donation will be released once he and Chan return from paternity and maternity leave.
Zuckerberg said he will remain chief executive of Facebook for "many, many years to come".
In a filing to the Securities and Exchange Commission, Facebook said that Zuckerberg "plans to sell or gift no more than a billion dollars of Facebook stock each year for the next three years, and that he intends to retain his majority voting position for the foreseeable future."

Rico says that even one percent won't be shabby...