(l) Private agency. A private non-profit agency, organization or institution is:
- (1) Any corporation, foundation, trust, association, cooperative, or accredited institution of higher education not under public supervision or control; and
- (2) Any other agency, organization or institution which operates primarily for scientific, education, service, charitable, or similar public purposes, but which is not under public supervision or control, and no part of the net earnings of which inures or may lawfully inure to the benefit of any private shareholder or individual, and which has been held by IRS to be tax-exempt under the provisions of section 501(c)(3) of the 1954 Internal Revenue Code.