Treas. Reg. § 1.401-2

(1) Under section 401(a)(2) a trust is not qualified unless under the trust instrument it is impossible (in the taxable year and at any time thereafter before the satisfaction of all liabilities to employees or their beneficiaries covered by the trust) for any part of the trust corpus or income to be used for, or diverted to, purposes other than for the exclusive benefit of such employees or their beneficiaries. This section does not apply to funds of the trust which are allocated to provide medical benefits described in section 401(h) as defined in paragraph (a) of § 1.401-14. For the rules prohibiting diversion of such funds and the requirement of reversion to the employer after satisfaction of all liabilities under the medical benefits account, see paragraph (c) (4) and (5) of § 1.401-14. For rules permitting reversion to the employer of amounts held in a section 415 suspense acount, see § 1.401(a)-2(b).

(2) As used in section 401(a)(2), the phrase “if under the trust instrument it is impossible” means that the trust instrument must definitely and affirmatively make it impossible for the nonexempt diversion or use to occur, whether by operation or natural termination of the trust, by power of revocation or amendment, by the happening of a contingency, by collateral arrangement, or by any other means. Although it is not essential that the employer relinquish all power to modify or terminate the rights of certain employees covered by the trust, it must be impossible for the trust funds to be used or diverted for purposes other than for the exclusive benefit of his employees or their beneficiaries.

(3) As used in section 401(a)(2), the phrase “purposes other than for the exclusive benefit of his employees or their beneficiaries” includes all objects or aims not solely designed for the proper satisfaction of all liabilities to employees or their beneficiaries covered by the trust.

(1) The intent and purpose in section 401(a)(2) of the phrase “prior to the satisfaction of all liabilities with respect to employees and their beneficiaries under the trust” is to permit the employer to reserve the right to recover at the termination of the trust, and only at such termination, any balance remaining in the trust which is due to erroneous actuarial computations during the previous life of the trust. A balance due to an “erroneous actuarial computation” is the surplus arising because actual requirements differ from the expected requirements even though the latter were based upon previous actuarial valuations of liabilities or determinations of costs of providing pension benefits under the plan and were made by a person competent to make such determinations in accordance with reasonable assumptions as to mortality, interest, etc., and correct procedures relating to the method of funding. For example, a trust has accumulated assets of $1,000,000 at the time of liquidation, determined by acceptable actuarial procedures using reasonable assumptions as to interest, mortality, etc., as being necessary to provide the benefits in accordance with the provisions of the plan. Upon such liquidation it is found that $950,000 will satisfy all of the liabilities under the plan. The surplus of $50,000 arises, therefore, because of the difference between the amounts actuarially determined and the amounts actually required to satisfy the liabilities. This $50,000, therefore, is the amount which may be returned to the employer as the result of an erroneous actuarial computation. If, however, the surplus of $50,000 had been accumulated as a result of a change in the benefit provisions or in the eligibility requirements of the plan, the $50,000 could not revert to the employer because such surplus would not be the result of an erroneous actuarial computation.

(2) The term “liabilities” as used in section 401(a)(2) includes both fixed and contingent obligations to employees. For example, if 1,000 employees are covered by a trust forming part of a pension plan, 300 of whom have satisfied all the requirements for a monthly pension, while the remaining 700 employees have not yet completed the required period of service, contingent obligations to such 700 employees have nevertheless arisen which constitute “liabilities” within the meaning of that term. It must be impossible for the employer (or other non employee) to recover any amounts other than such amounts as remain in the trust because of “erroneous actuarial computations” after the satisfaction of all fixed and contingent obligations. Furthermore, the trust instrument must contain a definite affirmative provision to this effect, irrespective of whether the obligations to employees have their source in the trust instrument itself, in the plan of which the trust forms a part, or in some collateral instrument or arrangement forming a part of such plan, and regardless of whether such obligations are, technically speaking, liabilities of the employer, of the trust, or of some other person forming a part of the plan or connected with it.