Facebook founder Mark Zuckerberg and wife Priscilla Chan named joint top US philanthropists

Facebook founder Mark Zuckerberg and his wife Priscilla Chan have been named joint top US philanthropists for 2013, after the couple donated 18 million Facebook shares to a Silicon Valley foundation.

The donation, worth over $970 million, topped 2013 US donations, outstripping donations by philanthropists such as Bill and Melinda Gates, according to the Chronicle of Philanthropy.

The couple made the $970 million donation to the Silicon Valley Community Foundation, a charity that manages and distributes charitable funds.

The Chronicle of Philanthropy said the share had helped to make the foundation one of the largest in the US.

Over the past two years, Zuckerberg and Chan have donated about 36 million Facebook shares to the foundation.

Philanthropists who had headed the list earlier, such as Microsoft co-founder Bill Gates and his wife, Melinda, had made good on previous years' pledges.

Bill and Melinda Gates gave their foundation slightly over $181.3 million last year, as they continued to honour a pledge of about $3.3 billion they made in 2004.

The top 50 American philanthropists are listed in The Chronicle every year. This year donations needed to top $37.5 million to reach the list.

Donations from the top contributors stood at $7.7 billion, with another $2.9 billion counted as pledges with much of the money going to non-profits in the health and science sectors.

The number two spot went to George Mitchell of Galveston, Texas, who bequeathed a $750 million grant for clean energy, natural gas sustainability, and water after his death.

Google's Sergey Brin and his wife Anne Wojcicki, founder of genomics firm 23andMe, who made it to the ninth spot on the list, together donated approximately $219 million to a variety of non-profits, which included the Michael J Fox Foundation for Parkinson's Research.

The magazine said, charities could look forward to even more big giving in 2014 as the economy improved.

Chronicle editor Stacy Palmer told the Associated Press that it was a sure sign that the economy was getting better and people were getting a lot less cautious, The Verge reported.