MARK Zuckerberg and his wife Priscilla Chan have said they plan to give away 99 per cent of their fortune in Facebook stock to a new charity.

The social network's chief executive made the pledge with his wife as they announced the birth of their first child.

Mr Zuckerberg said he had told the company that he would be selling or gifting up to $1 billion of his stock for each of the next three years. At current market prices, his shares in the company are now worth roughly $45 billion.

He said he would maintain voting control for the "foreseeable future."

Mr Zuckerberg, 31, and his wife also announced the birth of his daughter named Max.

"Priscilla and I are so happy to welcome our daughter Max into this world," Mr Zuckerberg said in a Facebook post.