Facebook Inc. co-founder and chief executive officer Mark Zuckerberg said on Tuesday he and his wife would give 99 percent of their Facebook shares to charitable purposes, Xinhua reported.

Proceeds of the holdings by the couple, Mark Zuckerberg and Priscilla Chan, of the public listed US social network currently worth $45 billion and will be managed by a new organisation known as the Chan Zuckerberg Initiative.

On his Facebook page, Zuckerberg posted "A letter to our daughter", who was born last week.

The couple promised that they would give away their money "during our lives" through wealth charitable donations, private investment and promotion of government-policy reform.

About the new organisation, formed as a limited liability company to be controlled by the couple, the 31-year-old Silicon Valley entrepreneur wrote that "our initial areas of focus will be personalised learning, curing disease, connecting people and building strong communities."

Meanwhile, Facebook said in a securities filing Zuckerberg has planned to give away "no more than $1 billion of Facebook stock each year for the next three years."