American Express (NYSE: AXP) will host its fourth annual Leadership Academy Global Alumni Summit in New York on April 16 and 17, celebrating eleven years of a transformative program that has developed more than 3,600 nonprofit and social purpose leaders. Seventy-two distinguished program alumni from around the world will have the opportunity to discuss best practices and participate in workshops with eleven premier leadership development organizations, including The Aspen Institute, Ashoka Changemakers, Center for Creative Leadership, Common Purpose, and Independent Sector.