The American Philatelic Society is the largest nonprofit stamp collecting foundation of philately in the world. Both the membership and interests of the society are worldwide. Wikipedia
Founded: September 14, 1886
Founder: John Kerr Tiffany
Endowment (2011): $5,563,869
Expenses (2011): $3,757,564
Membership (2023): 24,421
President: Cheryl Ganz
Revenue (2011): $4,139,814