Facebook COO Sheryl Sandberg has donated USD 31 million in Facebook stock to charity, days after her boss Mark Zuckerberg pledged to give away 99 per cent of his company shares.

Sanderberg, 46, donated 290,000 shares of Facebook stock at "a market value of roughly USD 31 million" to various charities, according to a Securities and Exchange Commission document.

The shares are now in the Sheryl Sandberg Philanthropy Fund, a donor-advised fund. Much of the money will go to causes that Sandberg has supported in the past. She has also given to women's empowerment groups, such as Lean In,to help support women in the workplace, SiliconValley.com reported today.

Sandberg also plans to give to anti-poverty efforts and educational groups. She is the co-chair of the Stand Up for Kids Campaign for Second Harvest Food Bank of Santa Clara & San Mateo Counties.

In 2014, Sandberg signed The Giving Pledge, the commitment by wealthy people to give the majority of their wealth to philanthropy in their lifetime, the report said.

In December, 31-year-old Facebook CEO Mark Zuckerberg announced the birth of his first child as he and his wife pledged to give away 99 per cent of his company shares worth a whopping USD 45 billion to make the world a "better place" for daughter Maxima and other children.