Except as provided in subsection (b), all assets of an employee benefit plan shall be held in trust by one or more trustees. Such trustee or trustees shall be either named in the trust instrument or in the plan instrument described in section 1102(a) of this title or appointed by a person who is a named fiduciary, and upon acceptance of being named or appointed, the trustee or trustees shall have exclusive authority and discretion to manage and control the assets of the plan, except to the extent that—

(1) the plan expressly provides that the trustee or trustees are subject to the direction of a named fiduciary who is not a trustee, in which case the trustees shall be subject to proper directions of such fiduciary which are made in accordance with the terms of the plan and which are not contrary to this chapter, or

(2) authority to manage, acquire, or dispose of assets of the plan is delegated to one or more investment managers pursuant to section 1102(c)(3) of this title.

The requirements of subsection (a) of this section shall not apply—

(1) to any assets of a plan which consist of insurance contracts or policies issued by an insurance company qualified to do business in a State;

(2) to any assets of such an insurance company or any assets of a plan which are held by such an insurance company;

to a plan—

(A) some or all of the participants of which are employees described in section 401(c)(1) of title 26; or

(B) which consists of one or more individual retirement accounts described in section 408 of title 26;

to a plan which the Secretary exempts from the requirement of subsection (a) and which is not subject to any of the following provisions of this chapter—

(A) part 2 of this subtitle,

(B) part 3 of this subtitle, or

(C) subchapter III of this chapter; or

(5) to a contract established and maintained under section 403(b) of title 26 to the extent that the assets of the contract are held in one or more custodial accounts pursuant to section 403(b)(7) of title 26.

(6) Any plan, fund or program under which an employer, all of whose stock is directly or indirectly owned by employees, former employees or their beneficiaries, proposes through an unfunded arrangement to compensate retired employees for benefits which were forfeited by such employees under a pension plan maintained by a former employer prior to the date such pension plan became subject to this chapter.

In the case of a contribution, or a payment of withdrawal liability under part 1 of subtitle E of subchapter III—

(1) Except as provided in paragraph (2), (3), or (4) or subsection (d), or under sections 1342 and 1344 of this title (relating to termination of insured plans), or under section 420 of title 26 (as in effect on July 31, 2015), the assets of a plan shall never inure to the benefit of any employer and shall be held for the exclusive purposes of providing benefits to participants in the plan and their beneficiaries and defraying reasonable expenses of administering the plan.

In the case of a contribution, or a payment of withdrawal liability under part 1 of subtitle E of subchapter III—

(A) In the case of a contribution, or a payment of withdrawal liability under part 1 of subtitle E of subchapter III— (i) if such contribution or payment is made by an employer to a plan (other than a multiemployer plan) by a mistake of fact, paragraph (1) shall not prohibit the return of such contribution to the employer within one year after the payment of the contribution, and (ii) if such contribution or payment is made by an employer to a multiemployer plan by a mistake of fact or law (other than a mistake relating to whether the plan is described in section 401(a) of title 26 or the trust which is part of such plan is exempt from taxation under section 501(a) of title 26), paragraph (1) shall not prohibit the return of such contribution or payment to the employer within 6 months after the plan administrator determines that the contribution was made by such a mistake.

(B) If a contribution is conditioned on initial qualification of the plan under section 401 or 403(a) of title 26, and if the plan receives an adverse determination with respect to its initial qualification, then paragraph (1) shall not prohibit the return of such contribution to the employer within one year after such determination, but only if the application for the determination is made by the time prescribed by law for filing the employer’s return for the taxable year in which such plan was adopted, or such later date as the Secretary of the Treasury may prescribe.

(C) If a contribution is conditioned upon the deductibility of the contribution under section 404 of title 26, then, to the extent the deduction is disallowed, paragraph (1) shall not prohibit the return to the employer of such contribution (to the extent disallowed) within one year after the disallowance of the deduction.

(3) In the case of a withdrawal liability payment which has been determined to be an overpayment, paragraph (1) shall not prohibit the return of such payment to the employer within 6 months after the date of such determination.

Upon termination of a pension plan to which section 1321 of this title does not apply at the time of termination and to which this part applies (other than a plan to which no employer contributions have been made) the assets of the plan shall be allocated in accordance with the provisions of section 1344 of this title, except as otherwise provided in regulations of the Secretary.

(1) Upon termination of a pension plan to which section 1321 of this title does not apply at the time of termination and to which this part applies (other than a plan to which no employer contributions have been made) the assets of the plan shall be allocated in accordance with the provisions of section 1344 of this title, except as otherwise provided in regulations of the Secretary.

(2) The assets of a welfare plan which terminates shall be distributed in accordance with the terms of the plan, except as otherwise provided in regulations of the Secretary.

(Pub. L. 93–406, title I, § 403, Sept. 2, 1974, 88 Stat. 876; Pub. L. 96–364, title III, § 310, title IV, §§ 402(b)(2), 410(a), 411(c), Sept. 26, 1980, 94 Stat. 1296, 1299, 1308; Pub. L. 100–203, title IX, § 9343(c), Dec. 22, 1987, 101 Stat. 1330–372; Pub. L. 101–239, title VII, §§ 7881(k), 7891(a)(1), 7894(e)(1)(A), (3), Dec. 19, 1989, 103 Stat. 2443, 2445, 2450; Pub. L. 101–508, title XII, § 12012(a), Nov. 5, 1990, 104 Stat. 1388–571; Pub. L. 103–465, title VII, § 731(c)(4)(B), Dec. 8, 1994, 108 Stat. 5004; Pub. L. 106–170, title V, § 535(a)(2)(B), Dec. 17, 1999, 113 Stat. 1934; Pub. L. 108–218, title II, § 204(b)(2), Apr. 10, 2004, 118 Stat. 609; Pub. L. 108–357, title VII, § 709(a)(2), Oct. 22, 2004, 118 Stat. 1551; Pub. L. 109–280, title I, § 108(a)(11), formerly § 107(a)(11), Aug. 17, 2006, 120 Stat. 819, renumbered Pub. L. 111–192, title II, § 202(a), June 25, 2010, 124 Stat. 1297; Pub. L. 112–141, div. D, title II, § 40241(b)(1), July 6, 2012, 126 Stat. 859; Pub. L. 114–41, title II, § 2007(b)(1), July 31, 2015, 129 Stat. 459.)