The project, called the Chan Zuckerberg Initiative, is structured as a limited liability company. That means, unlike a traditional charitable or philanthropic foundation, it can make political donations, lobby lawmakers, invest in businesses and recoup any profits from those investments.
"They are not behaving like a traditional philanthropy," said Leslie Lenkowsky, professor of public affairs and philanthropy at Indiana University. "They are instead trying to achieve philanthropic purposes using a business model."
Philanthropic foundations such as the one set up by Microsoft Corp co-founder Bill Gates typically support non-profit organizations, and they are required to pay out at least 5 percent of their assets in grants each year, a restriction the Zuckerbergs will not face.
Non-profit foundations like Gates's do not pay tax, whereas the Facebook chief executive's vehicle would pay tax on any profit generated.
Chan and Zuckerberg announced Tuesday, in a Facebook post disclosing the birth of their daughter Maxima, that 99 percent of the stock they hold in Facebook would go toward the philanthropic project over their lifetime.
At the stock's current price that stake is worth $45 billion. Zuckerberg said he will invest up to $1 billion of his shares each year over the next three years into the initiative. But the limited liability company structure means the couple do not have to sell those shares under the same time restraints they would face if the initiative was structured as a foundation, giving them more flexibility in how long they can hang on to the stock.
Thirty-one year old Zuckerberg, who holds majority voting power in the company, said he would maintain a controlling interest for the 'foreseeable future.'
The stock sales, if any, over the next three years are not expected to affect Facebook's share price because they are well-telegraphed and just a small fraction of both the company's $300 billion market cap and daily trading volume.