501(c)(3) organization

A 501(c)(3) organization, under American tax law, is a non-profit corporation recognized by the IRS as being operated for charitable or literary purposes (inter alia). Over the years, some SF clubs, particularly those running conventions, have gone through the process of obtaining this recognition, primarily because donations to a 501(c)(3) corporation may be tax-deductible for federal and state tax purposes, and because mundane companies are more cooperative with clubs showing this badge of respectability.