(a) Organizations subject to section 507(c) tax. Section 508(d)(1) provides that, in the case of gifts made after December 31, 1969, a deduction which would otherwise be allowable under section 2522 for a gift to or for the use of an organization upon which the tax provided by section 507(c) has been imposed shall not be allowed if the gift is made by the donor after notification is made under section 507(a) or if the donor is a substantial contributor (as defined in section 507(d)(2)) who makes such gift in his taxable year (as defined in section 441) which includes the first day on which action is taken by such organization that culminates in the imposition of the tax under section 507(c) and any subsequent taxable year. This paragraph does not apply if the entire amount of the unpaid portion of the tax imposed by section 507(c) is abated under section 507(g) by the Commissioner or his delegate.

(b) Taxable private foundations, section 4947 trusts, etc. Section 508(d)(2) provides that, in the case of gifts made after December 31, 1969, a deduction which would otherwise be allowable under section 2522 shall not be allowed if the gift is made to or for the use of—

(1) A private foundation or a trust described in section 4947(a)(2) in a taxable year of such organization for which such organization fails to meet the governing instrument requirements of section 508(e) (determined without regard to section 508(e)(2) (B) and (C)), or

(2) Any organization in a period for which it is not treated as an organization described in section 501(c)(3) by reason of its failure to give notification under section 508(a) of its status to the Commissioner.

(c) Foreign organizations with substantial support from foreign sources. Section 4948(c)(4) provides that, in the case of gifts made after December 31, 1969, a deduction which would otherwise be allowable under section 2522 for a gift to or for the use of a foreign organization which has received substantially all of its support (other than gross investment income) from sources without the United States shall not be allowed if the gift is made (1) after the date on which the Commissioner has published notice that he has notified such organization that it has engaged in a prohibited transaction, or (2) in a taxable year of such organization for which it is not exempt from taxation under section 501(a) because it has engaged in a prohibited transaction after December 31, 1969.