29 USC 1345 - Recapture of payments

(a) Authorization to recover benefits 
Except as provided in subsection (c) of this section, the trustee is authorized to recover for the benefit of a plan from a participant the recoverable amount (as defined in subsection (b) of this section) of all payments from the plan to him which commenced within the 3-year period immediately preceding the time the plan is terminated.
(b) Recoverable amount 
For purposes of subsection (a) of this section the recoverable amount is the excess of the amount determined under paragraph (1) over the amount determined under paragraph (2).
(1) The amount determined under this paragraph is the sum of the amount of the actual payments received by the participant within the 3-year period.
(2) The amount determined under this paragraph is the sum of
(A) the sum of the amount such participant would have received during each consecutive 12-month period within the 3 years if the participant received the benefit in the form described in paragraph (3),
(B) the sum for each of the consecutive 12-month periods of the lesser of
(i) the excess, if any, of $10,000 over the benefit in the form described in paragraph (3), or
(ii) the excess of the actual payment, if any, over the benefit in the form described in paragraph (3), and
(C) the present value at the time of termination of the participants future benefits guaranteed under this subchapter as if the benefits commenced in the form described in paragraph (3).
(3) The form of benefit for purposes of this subsection shall be the monthly benefit the participant would have received during the consecutive 12-month period, if he had elected at the time of the first payment made during the 3-year period, to receive his interest in the plan as a monthly benefit in the form of a life annuity commencing at the time of such first payment.
(c) Payments made on or after death or disability of participant; waiver of recovery in case of hardship 

(1) In the event of a distribution described in section 1343 (b)(7)1 of this title the 3-year period referred to in subsection (b) of this section shall not end sooner than the date on which the corporation is notified of the distribution.
(2) The trustee shall not recover any payment made from a plan after or on account of the death of a participant, or to a participant who is disabled (within the meaning of section 72 (m)(7) of title 26).
(3) The corporation is authorized to waive, in whole or in part, the recovery of any amount which the trustee is authorized to recover for the benefit of a plan under this section in any case in which it determines that substantial economic hardship would result to the participant or his beneficiaries from whom such amount is recoverable.
[1] See References in Text note below.