((a)) ** Plans covered** Except as provided in subsection (b), this subchapter applies to any plan (including a successor plan) which, for a plan year—

((1)) is an employee pension benefit plan (as defined in paragraph (2) of ) established or maintained—

((A)) by an employer engaged in commerce or in any industry or activity affecting commerce, or

((B)) by any employee organization, or organization representing employees, engaged in commerce or in any industry or activity affecting commerce, or

((C)) by both,

((2)) is, or has been determined by the Secretary of the Treasury to be, a plan described in , or which meets, or has been determined by the Secretary of the Treasury to meet, the requirements of .

((b)) ** Plans not covered** This section does not apply to any plan—

((1)) which is an individual account plan, as defined in paragraph (34) of ,

((2)) established and maintained for its employees by the Government of the United States, by the government of any State or political subdivision thereof, or by any agency or instrumentality of any of the foregoing, or to which the Railroad Retirement Act of 1935 or 1937 [ et seq.] applies and which is financed by contributions required under that Act, or which is described in the last sentence of

((3)) which is a church plan as defined in , unless that plan has made an election under , and has notified the corporation in accordance with procedures prescribed by the corporation, that it wishes to have the provisions of this part  apply to it,

((4))

((A)) established and maintained by a society, order, or association described in section 501(c)(8) or (9) of title 26, if no part of the contributions to or under the plan is made by employers of participants in the plan, or

((B)) of which a trust described in is a part;

((5)) which has not at any time after , provided for employer contributions;

((6)) which is unfunded and which is maintained by an employer primarily for the purpose of providing deferred compensation for a select group of management or highly compensated employees;

((7)) which is established and maintained outside of the United States primarily for the benefit of individuals substantially all of whom are nonresident aliens;

((8)) which is maintained by an employer solely for the purpose of providing benefits for certain employees in excess of the limitations on contributions and benefits imposed by on plans to which that section applies, without regard to whether the plan is funded, and, to the extent that a separable part of a plan (as determined by the corporation) maintained by an employer is maintained for such purpose, that part shall be treated for purposes of this subchapter, as a separate plan which is an excess benefit plan;

((9)) which is established and maintained exclusively for substantial owners;

((10)) of an international organization which is exempt from taxation under the International Organizations Immunities Act [ et seq.];

((11)) maintained solely for the purpose of complying with applicable workmen’s compensation laws or unemployment compensation or disability insurance laws;

((12)) which is a defined benefit plan, to the extent that it is treated as an individual account plan under paragraph (35)(B) of ; or

((13)) established and maintained by a professional service employer which does not at any time after , have more than 25 active participants in the plan.

((c)) ** Definitions**

((1)) For purposes of subsection (b)(1), the term “individual account plan” does not include a plan under which a fixed benefit is promised if the employer or his representative participated in the determination of that benefit.

((2)) For purposes of this paragraph and for purposes of subsection (b)(13)—

((A)) the term “professional service employer” means any proprietorship, partnership, corporation, or other association or organization (i) owned or controlled by professional individuals or by executors or administrators of professional individuals, (ii) the principal business of which is the performance of professional services, and

((B)) the term “professional individuals” includes but is not limited to, physicians, dentists, chiropractors, osteopaths, optometrists, other licensed practitioners of the healing arts, attorneys at law, public accountants, public engineers, architects, draftsmen, actuaries, psychologists, social or physical scientists, and performing artists.

((3)) In the case of a plan established and maintained by more than one professional service employer, the plan shall not be treated as a plan described in subsection (b)(13) if, at any time after , the plan has more than 25 active participants.

((d)) ** Substantial owner defined** For purposes of subsection (b)(9), the term “substantial owner” means an individual who, at any time during the 60-month period ending on the date the determination is being made—

((1)) owns the entire interest in an unincorporated trade or business,

((2)) in the case of a partnership, is a partner who owns, directly or indirectly, more than 10 percent of either the capital interest or the profits interest in such partnership, or

((3)) in the case of a corporation, owns, directly or indirectly, more than 10 percent in value of either the voting stock of that corporation or all the stock of that corporation.