Mark Zuckerberg and his wife pledged to give away virtually all of their $46 billion in Facebook Inc. shares, setting a new philanthropic benchmark by committing their massive fortune to charitable causes while still in their early 30s.

Facebook’s chief executive officer and his wife, Priscilla Chan, unveiled the plan in an open letter to their newborn daughter, Max (short for Maxima), in a Facebook post on Tuesday, promising to donate 99 percent of their stock in the social- networking company "during our lives."

The pledge puts Zuckerberg in the same league with other billionaires who are giving away the bulk of their wealth, including Warren Buffett and Bill Gates. The key difference is that Zuckerberg is starting at an earlier age, 31. The Bill & Melinda Gates Foundation was created in 2000, the year the Microsoft Corp. co-founder turned 45.

Zuckerberg doesn’t plan to contribute more than $1 billion a year for at least the next three years, Facebook said in a separate filing, meaning the CEO will maintain voting control of the Menlo Park, California-based company for the foreseeable future.

‘Too Important’

Zuckerberg outlined his philanthropic goals, which will focus on “advancing human potential and promoting equality,” in the letter to his daughter, who was born early last week. Zuckerberg will make long-term investments in areas such as health and education, while working to decrease inequality and building technology to bring about change.

"Our society has an obligation to invest now to improve the lives of all those coming into this world, not just those already here," Zuckerberg and Chan wrote. "But right now, we don’t always collectively direct our resources at the biggest opportunities and problems your generation will face."

He added that he will remain Facebook’s CEO for "many, many years to come, but these issues are too important to wait until you or we are older to begin this work.”

Different Audience

While Zuckerberg pegged the donation amount on the current value of his Facebook stock, the value of the gift could also grow. Shares of Facebook have climbed more than 180 percent since their market debut in 2012, and 90 percent of analysts who cover the company have a buy rating on the stock, meaning they expect it to go up. At the same time, the figure could be lower if investors determine in the future that Facebook’s stock is worth less.