Mark Zuckerberg (right) poses for a photo with Priscilla Chan (left) during a small wedding ceremony in Palo Alto, Calif. This photo was posted to Mark Zuckerberg's Facebook page on May 19, 2012.
Billionaire Mark Zuckerberg and his wife, Priscilla Chan, are some of the biggest American philanthropists, according to reports.
Facebook co-founder Zuckerberg and his wife contributed 18 million shares of Facebook stock worth about $498.9 million to the Silicon Valley Community Foundation which works with education and health programs, according to the Chronicle of Philanthropy. The couple have a net worth of about $9.6 billion and ranked No. 2 on the 2012 philanthropy list. In 2010, Zuckerberg also donated $100 million in stock to Newark, N.J. schools.
The Zuckerberg-Chans were edged out by No. 1 on the list, Warren Buffett, who contributed $3.1 billion to various charitable foundations in 2012. Buffett is worth approximately $44 billion.
What people should know is that Zuckerberg did cash out last year in Facebook's initial public offering to the tune of $1.1 billion so he is legitimately a billionaire, but most of his contributions have been in Facebook stock. Facebook stock has been fairly volatile since its IPO in 2012, so it's not altogether as stable as cash.