5 CFR 841.106: Basic records.

(a) Agencies having employees or Members subject to FERS must establish and maintain retirement accounts for those employees and Members.

(b)(1) The individual retirement record required by § 841.504(c) is the basic record for action on all claims for annuity or refund, and those pertaining to deceased employees, deceased Members, or deceased annuitants.

(2) When the official records repository for the records in question certifies that the records in question are lost, destroyed, or incomplete, OPM will accept such inferior or secondary evidence that it considers appropriate under the circumstances, and such inferior or secondary evidence is then admissible.

(3) Except as provided in paragraph (b)(2) of this section, inferior or secondary evidence will not be considered.