(Menlo Park, CA) -- Mark Zuckerberg is donating a billion dollars worth of stock to charity.

The Facebook CEO will give $18-million of his company's shares to the Silicon Valley Community Foundation. The new donation was part of a SEC filing that disclosed the planned sale of an additional 70 million shares of Facebook.

Zuckerberg's new donation is the largest ever to the foundation. His contribution last year of 18 million stocks was the second largest, when the stock was worth half the price.