Billionaire Philanthropists' New Favorite Cause

Self-made billionaires in the U.S. are giving the most to charity, donating on average $179.5 million per person over their lifetimes, according to a new study. In contrast, the typical ultra high net worth philanthropist worldwide gives $28.7 million over his or her lifetime.

While ultra-rich men tend to give far more than their female counterparts in total dollars, American women seem to be the most generous of all the ultra high net worth donor groups, if one looks at the percentage of net worth donated. As a group, American female billionaires gave away more than 13 percent of their wealth, and for those who inherited their wealth close to 19 percent.