To be described in section 501(c)(9) an organization must meet all of the following requirements:

(a) The organization is an employees' association,

(b) Membership in the association is voluntary,

(c) The organization provides for the payment of life, sick, accident, or other benefits to its members or their dependents or designated beneficiaries, and substantially all of its operations are in furtherance of providing such benefits, and

(d) No part of the net earnings of the organization inures, other than by payment of the benefits referred to in paragraph (c) of this section, to the benefit of any private shareholder or individual.