29 C.F.R. § 4041A.22

(a) Except as provided in paragraph (b), the plan sponsor shall pay any benefit attributable to employer contributions, other than a death benefit, only in the form of an annuity.

(b) The plan sponsor may pay a benefit in a form other than an annuity if—

(c) Except to the extent provided in the next sentence, the plan sponsor shall not pay benefits in excess of the amount that is nonforfeitable under the plan as of the date of termination, unless authorized to do so by the PBGC pursuant to § 4041A.27. Subject to the restriction stated in paragraph (d) of this section, however, the plan sponsor may pay a qualified preretirement survivor annuity with respect to a participant who died after the date of termination.

(d) The payment of benefits subject to reduction shall be discontinued to the extent provided in § 4281.31 if the plan sponsor determines, in accordance with § 4041A.24, that the plan's assets are insufficient to provide all nonforfeitable benefits.

(e) The plan sponsor shall, to the extent provided in § 4281.41, suspend the payment of nonguaranteed benefits if the plan sponsor determines, in accordance with § 4041A.25, that the plan is insolvent.

(f) The plan sponsor shall, to the extent required by § 4281.42, make retroactive payments of suspended benefits if it determines under that section that the level of the plan's available resources requires such payments.