Stephen Lam / Reuters

Mark Zuckerberg and Priscilla Chan announced the birth of their daughter Max on Tuesday in a long and heartfelt note on Facebook. The birth announcement was accompanied by something that quickly eclipsed news of their bundle of joy: A pledge to give away the majority of their fortune to a charitable initiative that will focus on “personalized learning, curing disease, connecting people and building strong communities.”

We will give 99% of our Facebook shares -- currently about $45 billion -- during our lives to advance this mission. We know this is a small contribution compared to all the resources and talents of those already working on these issues. But we want to do what we can, working alongside many others.

The announcement was immediately hailed for its generosity. The Zuckerbergs said the money will channeled throughout the couple’s lifetimes through the Chan Zuckerberg Initiative. The couple had previously signed The Giving Pledge, first conceived by Bill and Melinda Gates, Warren Buffett, and others, which committed several ultra-wealthy donors to give away their fortunes.

Nevertheless, the magnitude of Tuesday’s announcement was stunning. As Politico’s Alex Weprin pointed out, the announcement required a filing with the U.S. Security and Exchanges Commission.

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