26 U.S. Code § 508 – Special rules with respect to section 501(c)(3) organizations
(a) New organizations must notify the Secretary that they are applying for recognition of section 501(c)(3) status
Except as provided in subsection (c), an organization organized after October 9, 1969, shall not be treated as an organization described in section 501(c)(3)—
(1) unless it has given notice to the Secretary in such manner as the Secretary may by regulations prescribe, that it is applying for recognition of such status, or
(2) for any period before the giving of such notice, if such notice is given after the time prescribed by the Secretary by regulations for giving notice under this subsection.
(b) Presumption that organizations are private foundations
Except as provided in subsection (c), any organization (including an organization in existence on October 9, 1969) which is described in section 501(c)(3) and which does not notify the Secretary, at such time and in such manner as the Secretary may by regulations prescribe, that it is not a private foundation shall be presumed to be a private foundation.
(c) Exceptions
(1) Mandatory exceptions
Subsections (a) and (b) shall not apply to—
(A) churches, their integrated auxiliaries, and conventions or associations of churches, or
(B) any organization which is not a private foundation (as defined in section 509(a)) and the gross receipts of which in each taxable year are normally not more than $5,000.