12/18/2012 07:11 pm ET Updated Feb 17, 2013

Mark Zuckerberg's Donation To Silicon Valley Community Foundation Is His Biggest Yet

Facebook CEO Mark Zuckerberg announced -- via Facebook, of course -- that he and his wife, Priscilla Chan, have donated 18 million Facebook shares to the Silicon Valley Community Foundation, a non-profit organization that works with philanthropists to manage their donations.

With Facebook stock worth around $27 a share at the time of this post, Zuckerberg and Chan's donation is worth just south of $500 million, making it his largest charitable donation yet. Zuckerberg said in his Facebook post that they plan to look for "areas in education and health to focus on next."

As Zuckerberg noted in his Facebook status update -- which had been "liked" by 27,588 people just 18 minutes after it was published -- he and Chan signed the Gates and Buffett-endorsed Giving Pledge in 2010, signaling their commitment to donating a majority of their wealth to philanthropic efforts.

Zuckerberg was worth over $10 billion as of August 2012, and will take a salary of $1 per year starting in 2013.

The donation to the Silicon Valley Community Foundation marks the Facebook co-founder's second major act of philanthropy in as many years: In September 2010, Zuckerberg donated $100 million in Facebook stock to help Newark schools.

Zuckerberg's post reads as follows (You can see it on Facebook here):

Two years ago, Priscilla and I signed The Giving Pledge, committing to donate the majority of the money we earn to charity.

Our first major project has been around education reform with Startup: Education in Newark, NJ. I'm really proud of the work we've done there, helping leaders like Governor Chris Christie and Mayor Cory Booker sign the most progressive teachers contract in our country, opening four new district high schools, 11 new charter schools and more.

Today, in order to lay the foundation for new projects, we've made a contribution of 18 million Facebook shares to the Silicon Valley Community Foundation. Together, we will look for areas in education and health to focus on next. I'm hopeful we'll be able to have as positive an impact in our next set of projects.