Big philanthropic bets have the power to change society for the better. In fact, the majority of the most successful nonprofit organizations and social movements over the past decades have had at least one $10M or greater philanthropic gift behind them. While supporting ambitious social change is the primary motivation for the large majority of philanthropists, 80-percent of their big bets go to traditional institutional giving such as universities and medical research. Why does this aspiration gap exist, and what can be done to close it?