The rich and famous who gave away over $1 billion in charity

Mark Zuckerberg's pledge to give away Facebook stock worth $45 billion puts him at the forefront of a philanthropic class that has promised to donate most of their fortunes.

The elite list includes three men - Microsoft co-founder Bill Gates, stock market sage Warren Buffet and Oracle co-founder Larry Ellison - who are wealthier than Zuckerberg, according to Forbes magazine's latest rankings.

That trio and Zuckerberg are among the 138 wealthy individuals and families who have signed a "giving pledge" committing them to give away most of their fortunes in an attempt to fix society's problems.

Zuckerberg, 31, and his wife Priscilla Chan, 30, waited until the birth of their first child, a girl named Max, to reveal their intention to give away all but 1 per cent of the Facebook stock that accounts for most of their fortune.

Here's a look at the donations of at least $1 billion announced during the past decade, as tracked by the Chronicle of Philanthropy:

• Buffet pledged to donate a total of $43.6 billion in 2006 to the Bill & Melinda Gates Foundation and three other foundations.
• Helen Walton, the wife of Wal-Mart Stores founder Sam Walton, donated her estimated fortune of $16.4 billion to a family foundation after her death in 2007.
• Leona Helmsley, who made her fortune in hotels and other real estate, donated an estimated $5.2 billion to charitable trust after her death in 2007.
• Medical entrepreneur James Sorenson donated an estimated $4.5 billion to a family foundation after his death in 2008.
• Buffett pledged to donate $3.1 billion to three different foundations in 2012.
• Zuckerberg donated $1.5 billion to the Silicon Valley Community Foundation in 2012 and 2013.
• Hotelier Barron Hilton pledged to donate $1.2 billion to the Conrad N. Hilton Foundation in 2007.
• Former investment banker Peter Peterson donated $1 billion to a foundation bearing his name in 2008.
• Ralph Wilson Jr., the longtime owner the National Football League's Buffalo Bills, donated $1 billion to a foundation bearing his name after his death in 2014.