You’ve likely heard by now that Facebook founder Mark Zuckerberg and his wife, Priscilla Chan, will be pledging 99% of their Facebook shares (currently $45B) to charity during their lifetimes. The Chan Zuckerberg Initiative, announced in a letter to their newborn daughter, has an unusual structure (though we say nothing is more unusual than the act of sending a letter), sheltering the couple from some of the typical requirements of charitable giving, reports CNBC.

The couple’s Facebook shares will be transferred to a new limited liability company. These shares or the net after-tax proceeds from the sale of the shares will be used to advance the mission of the Chan Zuckerberg Initiative. The couple will decide how best to allocate the funds over their life. Experts say the LLC structure provides the couple more flexibility and control over their giving and allows them to change their minds about what they want to fund and how much they want to give over their lifetimes. [CNBC]