26 U.S. Code § 501 - Exemption from tax on corporations, certain trusts, etc.
(a) Exemption from taxation An organization described in subsection (c) or (d) or section 401(a) shall be exempt from taxation under this subtitle unless such exemption is denied under section 502 or 503.
(c) List of exempt organizations The following organizations are referred to in subsection (a):
(3) Corporations, and any community chest, fund, or foundation, organized and operated exclusively for religious, charitable, scientific, testing for public safety, literary, or educational purposes, or to foster national or international amateur sports competition (but only if no part of its activities involve the provision of athletic facilities or equipment), or for the prevention of cruelty to children or animals, no part of the net earnings of which inures to the benefit of any private shareholder or individual, no substantial part of the activities of which is carrying on propaganda, or otherwise attempting, to influence legislation (except as otherwise provided in subsection (h)), and which does not participate in, or intervene in (including the publishing or distributing of statements), any political campaign on behalf of (or in opposition to) any candidate for public office.
26 U.S. Code § 508 - Special rules with respect to section 501(c)(3) organizations
(a) New organizations must notify 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.
26 U.S. Code § 6033 - Returns by exempt organizations
(a) Organizations required to file
(1) In general
Except as provided in paragraph (3), every organization exempt from taxation under section 501(a) shall file an annual return, stating specifically the items of gross income, receipts, and disbursements, and such other information for the purpose of carrying out the internal revenue laws as the Secretary may by forms or regulations prescribe, and shall keep such records, render under oath such statements, make such other returns, and comply with such rules and regulations as the Secretary may from time to time prescribe; except that, in the discretion of the Secretary, any organization described in section 401(a) may be relieved from stating in its return any information which is reported in returns filed by the employer which established such organization.
(3) Exceptions from filing
(A) Mandatory exceptions
Paragraph (1) shall not apply to—
(i) churches, their integrated auxiliaries, and conventions or associations of churches
26 U.S. Code § 170 - Charitable, etc., contributions and gifts
(a) Allowance of deduction
(1) General rule
There shall be allowed as a deduction any charitable contribution (as defined in subsection (c)) payment of which is made within the taxable year. A charitable contribution shall be allowable as a deduction only if verified under regulations prescribed by the Secretary.
(b) Percentage limitations
(1) Individuals
In the case of an individual, the deduction provided in subsection (a) shall be limited as provided in the succeeding subparagraphs.
(A) General rule
Any charitable contribution to—
(i) a church or a convention or association of churches,
(ii) an educational organization which normally maintains a regular faculty and curriculum and normally has a regularly enrolled body of pupils or students in attendance at the place where its educational activities are regularly carried on,
(iii) an organization the principal purpose or functions of which are the providing of medical or hospital care or medical education or medical research, if the organization is a hospital, or if the organization is a medical research organization directly engaged in the continuous active conduct of medical research in conjunction with a hospital, and during the calendar year in which the contribution is made such organization is committed to spend such contributions for such research before January 1 of the fifth calendar year which begins after the date such contribution is made,
(iv) an organization which normally receives a substantial part of its support (exclusive of income received in the exercise or performance by such organization of its charitable, educational, or other purpose or function constituting the basis for its exemption under section 501(a)) from the United States or any State or political subdivision thereof or from direct or indirect contributions from the general public, and which is organized and operated exclusively to receive, hold, invest, and administer property and to make expenditures to or for the benefit of a college or university which is an organization referred to in clause (ii) of this subparagraph and which is an agency or instrumentality of a State or political subdivision thereof, or which is owned or operated by a State or political subdivision thereof or by an agency or instrumentality of one or more States or political subdivisions,
(v) a governmental unit referred to in subsection (c)(1),
(vi) an organization referred to in subsection (c)(2) which normally receives a substantial part of its support (exclusive of income received in the exercise or performance by such organization of its charitable, educational, or other purpose or function constituting the basis for its exemption under section 501(a)) from a governmental unit referred to in subsection (c)(1) or from direct or indirect contributions from the general public,
(vii) a private foundation described in subparagraph (F),
(viii) an organization described in section 509(a)(2) or (3), or
(ix) an agricultural research organization directly engaged in the continuous active conduct of agricultural research (as defined in section 1404 of the National Agricultural Research, Extension, and Teaching Policy Act of 1977) in conjunction with a land-grant college or university (as defined in such section) or a non-land grant college of agriculture (as defined in such section), and during the calendar year in which the contribution is made such organization is committed to spend such contribution for such research before January 1 of the fifth calendar year which begins after the date such contribution is made,
shall be allowed to the extent that the aggregate of such contributions does not exceed 50 percent of the taxpayer’s contribution base for the taxable year.
(c) Charitable contribution defined
For purposes of this section, the term “charitable contribution” means a contribution or gift to or for the use of—
(1) A State, a possession of the United States, or any political subdivision of any of the foregoing, or the United States or the District of Columbia, but only if the contribution or gift is made for exclusively public purposes.
(2) A corporation, trust, or community chest, fund, or foundation—
(A) created or organized in the United States or in any possession thereof, or under the law of the United States, any State, the District of Columbia, or any possession of the United States;
(B) organized and operated exclusively for religious, charitable, scientific, literary, or educational purposes, or to foster national or international amateur sports competition (but only if no part of its activities involve the provision of athletic facilities or equipment), or for the prevention of cruelty to children or animals;
(C) no part of the net earnings of which inures to the benefit of any private shareholder or individual; and
(D) which is not disqualified for tax exemption under section 501(c)(3) by reason of attempting to influence legislation, and which does not participate in, or intervene in (including the publishing or distributing of statements), any political campaign on behalf of (or in opposition to) any candidate for public office.
A contribution or gift by a corporation to a trust, chest, fund, or foundation shall be deductible by reason of this paragraph only if it is to be used within the United States or any of its possessions exclusively for purposes specified in subparagraph (B). Rules similar to the rules of section 501(j) shall apply for purposes of this paragraph.
(3) A post or organization of war veterans, or an auxiliary unit or society of, or trust or foundation for, any such post or organization—
(A) organized in the United States or any of its possessions, and
(B) no part of the net earnings of which inures to the benefit of any private shareholder or individual.
26 U.S. Code § 509 - Private foundation defined
(a) General rule
For purposes of this title, the term “private foundation” means a domestic or foreign organization described in section 501(c)(3) other than—
(1) an organization described in section 170(b)(1)(A) (other than in clauses (vii) and (viii));
(2) an organization which—
(A) normally receives more than one-third of its support in each taxable year from any combination of—
(i) gifts, grants, contributions, or membership fees, and
(ii) gross receipts from admissions, sales of merchandise, performance of services, or furnishing of facilities, in an activity which is not an unrelated trade or business (within the meaning of section 513), not including such receipts from any person, or from any bureau or similar agency of a governmental unit (as described in section 170(c)(1)), in any taxable year to the extent such receipts exceed the greater of $5,000 or 1 percent of the organization’s support in such taxable year,
from persons other than disqualified persons (as defined in section 4946) with respect to the organization, from governmental units described in section 170(c)(1), or from organizations described in section 170(b)(1)(A) (other than in clauses (vii) and (viii)), and
(B) normally receives not more than one-third of its support in each taxable year from the sum of—
(i) gross investment income (as defined in subsection (e)) and
(ii) the excess (if any) of the amount of the unrelated business taxable income (as defined in section 512) over the amount of the tax imposed by section 511;
(3) an organization which—
(A) is organized, and at all times thereafter is operated, exclusively for the benefit of, to perform the functions of, or to carry out the purposes of one or more specified organizations described in paragraph (1) or (2),
(B) is—
(i) operated, supervised, or controlled by one or more organizations described in paragraph (1) or (2),
(ii) supervised or controlled in connection with one or more such organizations, or
(iii) operated in connection with one or more such organizations, and
(C) is not controlled directly or indirectly by one or more disqualified persons (as defined in section 4946) other than foundation managers and other than one or more organizations described in paragraph (1) or (2)