5 CFR § 1651.10 - Deceased and non-existent beneficiaries.
(a) Designated beneficiary dies before participant. The share of any designated beneficiary who predeceases the participant will be paid pro rata to the participant's other designated beneficiary or beneficiaries. If no designated beneficiary survives the participant, the account will be paid according to the order of precedence set forth in § 1651.2(a).
(b) Trust designated as beneficiary but not in existence. If a participant designated a trust or other entity as a beneficiary and the entity does not exist on the date of the participant's death, or is not created by will or other document that is effective upon the participant's death, the amount designated to the entity will be paid in accordance with the rules of paragraph (a) of this section, as if the trust were a beneficiary that predeceased the participant.
(c) Non-designated beneficiary dies before participant. If a beneficiary other than a beneficiary designated on a TSP designation of beneficiary dies before the participant, the beneficiary's share will be paid equally to other living beneficiaries bearing the same relationship to the participant as the deceased beneficiary. However, if the deceased beneficiary is a child of the participant, payment will be made to the deceased child's descendants, if any. If there are no other beneficiaries bearing the same relationship or, in the case of children, there are no descendants of deceased children, the deceased beneficiary's share will be paid to the person(s) next in line according to the order of precedence.
(d) Beneficiary dies after participant but before payment. If a beneficiary dies after the participant, the beneficiary's share will be paid to the beneficiary's estate. A copy of a beneficiary's certified death certificate is required in order to establish that the beneficiary has died, and when.