Facebook founder Mark Zuckerberg and his wife Priscilla Chan have  pledged to give away 99% of their shares in Facebook to charity. Not today, but over the years, step by step.

The value of the shares that will be given to the newly formed Chan Zuckerberg Initiative is currently worth more than $45 billion.

The donation is motivated  by the birth of Zuckerberg and Chan’s daughter. Both argue

– to make her world a better place, and

to improve the world in the future.

Zuckerberg made the pledge public in an open letter to her:

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.
 Zuckerberg will keep a controlling interest in Facebook “for the foreseeable future”.