A section 509(a)(3) supporting organization must file Form 990 or 990-EZ PDF. A supporting organization must file annually even if would otherwise fall within a filing exception because— Its gross receipts are normally $50,000 or less, It is a church or church-affiliated organization described in Revenue Procedure 96-10 PDF, or It is an affiliate of a governmental unit described in Revenue Procedure 95-48 PDF. The following supporting organizations are not required to file an annual return, however: An integrated auxiliary of a church described in Regulations section 1.6033-2(h), The exclusively religious activities of a religious order, or An organization, the gross receipts of which are normally not more than $5,000, that supports a section 501(c)(3) religious organization. If the organization is described in (3) but not in (1) or (2), then it must submit Form 990-N unless it voluntarily files Form 990 or 990-EZ. Additional information Publication 1828 PDF, Tax Guide for Churches and Religious Organizations Form 990 Series Forms and Instructions