26 U.S.C. § 6113: Disclosure of nondeductibility of contributions

Each fundraising solicitation by (or on behalf of) an organization to which this section applies shall contain an express statement (in a conspicuous and easily recognizable format) that contributions or gifts to such organization are not deductible as charitable contributions for Federal income tax purposes. is described in subsection (c) (other than paragraph (1) thereof) or (d) of section 501 and exempt from taxation under section 501(a), is a political organization (as defined in section 527(e)), or was an organization described in subparagraph (A) or (B) at any time during the 5-year period ending on the date of the fundraising solicitation or is a successor to an organization so described at any time during such 5-year period. This section shall not apply to any organization the gross receipts of which in each taxable year are normally not more than $100,000. The Secretary may treat any group of 2 or more organizations as 1 organization for purposes of subparagraph (A) where necessary or appropriate to prevent the avoidance of this section through the use of multiple organizations. For purposes of paragraph (1), an organization described in section 170(c)(4) shall be treated as described in section 170(c) only with respect to solicitations for contributions or gifts which are to be used exclusively for purposes referred to in section 170(c)(4). in written or printed form, by television or radio, or by telephone. The term “fundraising solicitation” shall not include any letter or telephone call if such letter or call is not part of a coordinated fundraising campaign soliciting more than 10 persons during the calendar year.