Mark D. Lerner, representing members of the Lerner, Cohen, Tanenbaum family, is a principal owner of the Washington Nationals Baseball Club and a principal of Lerner Enterprises, a real estate development, management and investment company concentrated in the Washington, D.C., metropolitan area.  Mr. Lerner and his family are leading philanthropists in the region, supporting numerous organizations and causes.   He currently serves as a trustee of the Jewish Community Center of Greater Washington, and as a member of the board of Hillel at The George Washington University.