A couple of months ago, Facebook founder Mark Zuckerberg and his wife Priscilla Chan had a baby girl called Maxima. The baby was much wanted and came after a number of miscarriages. In a spectacular act of gratitude, the couple promised to give 99% of their wealth to charity in their lifetimes.

That was some promise, especially when you are 31 and among the top 10 wealthiest people in the world. Indeed, last week alone, Zuckerberg’s wealth increased by several billion dollars as the stock market reacted well to Facebook’s most recent accounts.