plan sponsor
(16) (A) The term “administrator” means— (i) the person specifically so designated by the terms of the instrument under which the plan is operated; (ii) if an administrator is not so designated, the plan sponsor; or (iii) in the case of a plan for which an administrator is not designated and a plan sponsor cannot be identified, such other person as the Secretary may by regulation prescribe. (B) The term “plan sponsor” means (i) the employer in the case of an employee benefit plan established or maintained by a single employer, (ii) the employee organization in the case of a plan established or maintained by an employee organization, (iii) in the case of a plan established or maintained by two or more employers or jointly by one or more employers and one or more employee organizations, the association, committee, joint board of trustees, or other similar group of representatives of the parties who establish or maintain the plan, or (iv) in the case of a pooled employer plan, the pooled plan provider.