(a) A corporation described in section 501(c)(2) and otherwise exempt from tax under section 501(a) is taxable upon its unrelated business taxable income. For taxable years beginning before January 1, 1970, see § 1.511-2(c)(4). Since a corporation described in section 501(c)(2) cannot be exempt under section 501(a) if it engages in any business other than that of holding title to property and collecting income therefrom, it cannot have unrelated business taxable income as defined in section 512 other than income which is treated as unrelated business taxable income solely because of the applicability of section 512(a)(3)(C); or debt financed income which is treated as unrelated business taxable income solely because of section 514; or certain interest, annuities, royalties, or rents which are treated as unrelated business taxable income solely because of section 512(b) (3)(B)(ii) or (13). Similarly, exempt status under section 501(c)(2) shall not be affected where certain rents from personal property leased with real property are treated as unrelated business taxable income under section 512(b)(3)(A)(ii) solely because such rents attributable to such personal property are more than incidental when compared to the total rents received or accrued under the lease, or under section 512(b)(3)(B)(i) solely because such rents attributable to such personal property exceed 50 percent of the total rents received or accrued under the lease.

(b) A corporation described in section 501(c)(2) cannot accumulate income and retain its exemption, but it must turn over the entire amount of such income, less expenses, to an organization which is itself exempt from tax under section 501(a).