5 CFR § 1651.16 - Missing and unknown beneficiaries.
(a) Locate and identify beneficiaries.
(1) The TSP record keeper will attempt to identify and locate all potential beneficiaries.
(2) If a beneficiary is not identified and located, and at least one year has passed since the date of the participant's death, the beneficiary will be treated as having predeceased the participant and the beneficiary's share will be paid in accordance with § 1651.10
(b) Payment to known beneficiaries. If all potential beneficiaries are known but one or more beneficiaries (and not all) appear to be missing, payment of part of the participant's account may be made to the known beneficiaries. The lost or unidentified beneficiary's share may be paid in accordance with paragraph (a) of this section at a later date.
(c) Abandoned account. If no beneficiaries of the account are located, the account will be considered abandoned and the funds will revert to the TSP. If there are multiple beneficiaries and one or more of them refuses to cooperate in the TSP record keeper's search for the missing beneficiary, the missing beneficiary's share will be considered abandoned. In such circumstances, the account can be reclaimed if the missing beneficiary is found at a later date. However, earnings will not be credited from the date the account is abandoned. The TSP may require the beneficiary to apply for the death benefit in the form and manner prescribed by the TSP record keeper and submit proof of identity and relationship to the participant.