Facebook CEO and Founder Mark Zuckerberk comes in second place to Warren Buffett in 2012...in terms of Charitable Giving-to the tune of $500 Million!

(CNN) -- Facebook's Mark Zuckerberg and his wife were the second-biggest charitable donors in the United States last year, appearing behind only billionaire Warren Buffett on a list of the nation's most generous philanthropists.

Zuckerberg, along with wife Priscilla Chan, gave roughly half a billion dollars ($498.8 million) to the Silicon Valley Community Foundation, according to The Chronicle of Philanthropy.

The group released its annual Philanthropy 50 over the weekend.

The Facebook founder and CEO was one of three tech-industry titans in the list's top five.

Microsoft co-founder Paul Allen was fourth, with $309 million in contributions, mostly to the Allen Institute for Brain Science.

And Google co-founder Sergey Brin and wife Anne Wojcicki, co-founder of genetic-testing company 23andME, were fifth, putting $223 million into their Brin Wojcicki Foundation.

Warren Buffet kept on giving in 2012 - to the tune of over $21M. Ultimately plans to give his entire fortune of over $50 Billion to charitable causes.

OMAHA, Neb. (AP) — Billionaire Warren Buffett gave Berkshire Hathaway stock worth $21.6 million away in the second half of 2012.

Buffett revealed the donations Monday. Buffett, who is Berkshire's chairman and CEO, made donations of Class B shares to four unnamed charities and three individuals between September and December.

The biggest single gift reported Monday was 172,375 shares worth $16.6 million given to a nonprofit.

These gifts are in addition to the 22.4 million Class B Berkshire shares Buffett gave to the Bill & Melinda Gates Foundation and the four Buffett family foundations that are slated to eventually distribute most of Buffett's fortune.

Buffett has said he plans to eventually donate all of his 350,000 Class A and 3.5 million Class B shares of Berkshire stock worth more than $51 billion to charities.