Treas. Reg. § 1.501(c)(12)-1

(a) An organization described in section 501(c)(12) must receive at least 85 percent of its income from amounts collected from members for the sole purpose of meeting losses and expenses. If an organization issues policies for stipulated cash premiums, or if it requires advance deposits to cover the cost of the insurance and maintains investments from which more than 15 percent of its income is derived, it is not entitled to exemption. On the other hand, an organization may be entitled to exemption, although it makes advance assessments for the sole purpose of meeting future losses and expenses, provided that the balance of such assessments remaining on hand at the end of the year is retained to meet losses and expenses or is returned to members.

(b) The phrase of a purely local character applies to benevolent life insurance associations, and not to the other organizations specified in section 501(c)(12). It also applies to any organization seeking exemption on the ground that it is an organization similar to a benevolent life insurance association. An organization of a purely local character is one whose business activities are confined to a particular community, place, or district, irrespective, however, of political subdivisions. If the activities of an organization are limited only by the borders of a State it cannot be considered to be purely local in character.

(c) For taxable years of a mutual or cooperative telephone company beginning after December 31, 1974, the 85 percent member-income test described in paragraph (a) of this section is applied without taking into account income received or accrued from another telephone company for the performance of communication services involving the completion of long distance calls to, from, or between members of the mutual or cooperative telephone company. For example, if, in one year, a cooperative telephone company receives $85x from its members for telephone calls, $15x as interest income, and $20x as credits under long distance interconnection agreements with other telephone companies for the performance of communication services involving the completion of long distance calls to, from, or between the cooperative's members (whether or not the credits may be offset, in whole or in part, by amounts due the other companies under the interconnection agreements), the member-income fraction is calculated without taking into account, either in the numerator or denominator, the $20x credits received from the other telephone companies. In this example, the 85 percent member-income test is satisfied because at least 85 percent