Mark Zuckerberg says he's giving away 99% of his Facebook shares — worth $45 billion today

Mark Zuckerberg announced Tuesday that he's giving away 99% of his Facebook shares — valued at $45 billion today —during his lifetime.

The Facebook CEO announced the news in a letter to his newborn daughter, Max.

Zuckerberg and his wife, Priscilla Chan, created the Chan Zuckerberg Initiative. Its mission mimics much of what Zuckerberg and Chan's donations have focused on in the past: personalized learning, curing diseases, and connecting people.

The move is not surprising given that five years ago Zuckerberg signed the "Giving Pledge" — along with other tech billionaires such as Bill Gates — to give away the majority of his wealth.

Zuckerberg will retain control of the majority of Facebook voting rights for the foreseeable future, and has limited himself to giving away no more than $1 billion in Facebook stock each year for the next three years, according to an SEC filing.

Because of Facebook's unique dual-class structure, where he owns special super voting shares, Zuckerberg can give away ordinary shares of stock while still maintaining majority control of the social network he founded in 2004.

The Facebook CEO announced his donation in a letter to his newborn daughter, Max.

Today your mother and I are committing to spend our lives doing our small part to help solve these challenges. I will continue to serve as 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. By starting at a young age, we hope to see compounding benefits throughout our lives.

As you begin the next generation of the Chan Zuckerberg family, we also begin the Chan Zuckerberg Initiative to join people across the world to advance human potential and promote equality for all children in the next generation. Our initial areas of focus will be 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.

Chan and Zuckerberg made a video before Max was born about their new project.'Wow'

With the announcement, philanthropists such as Bill Gates and Bono congratulated the young couple on giving away the majority of their money.

Bill and Melinda Gates wrote in a press release:

As for your decision to give back so generously, and to deepen your commitment now, the first word that comes to mind is: Wow. The example you’re setting today is an inspiration to us and the world. We can be confident of this: Max and every child born today will grow up in a world that is better than the one we know now. As you say, 'seeds planted now will grow.' Your work will bear fruit for many decades to come.

Zuckerberg and Chan have already donated more than $1.6 billion to charity in the past decade, including a $100 million gift to the Newark Public School System, a $25 million donation to the CDC to stop the spread of Ebola, and a $120 million commitment to education in the Bay Area.

Bono, the lead singer of U2, said:

In these troubled times, Mark and Priscilla’s announcement today is life-affirming and will be life-changing for tens of millions of people. The scope of their commitment will be stunning to many, but to their friends it is not surprising. This is who they are. Community for Mark and Priscilla isn’t just a word, it’s a core value. I can’t wait to see what they achieve, not just with their wealth, but by their example and with their ingenuity, creativity and vision applied to some of the biggest challenges — and opportunities — of our time.