29 C.F.R. § 9.12
(1) Nondisplaced employees.
(2) Predecessor contract's non-service workers.
(3) Employee's past performance.
(ii) A successor contractor must presume that there would be no just cause to discharge any employees working under the predecessor contract in the last month of performance, unless it can demonstrate a reasonable belief to the contrary that is based upon reliable evidence provided by a knowledgeable source, such as the predecessor contractor and its subcontractors, the local supervisor, the employee, or the contracting agency. This determination must be made on an individual basis for each employee. Information regarding the general performance of the predecessor contractor is not sufficient to claim this exception.
(4) Nonfederal work.
(ii) Where, in accordance with this authority to employ fewer employees, a successor contractor does not offer employment to all the predecessor contract employees, the obligation to offer employment will continue for 90 calendar days after the successor contractor's first date of performance on the contract. The contractor's obligation under this part will end when all of the predecessor contract employees have received a bona fide job offer, as described in § 9.12(b), or when the 90-day window of obligation has expired. The following three examples demonstrate the principle.
(2) Records to be retained.
(iv) Every contractor that makes retroactive payment of wages or compensation under the supervision of the Administrator pursuant to § 9.23(b), must:
(B) Prepare a report of each such payment on a receipt form provided by or authorized by the Wage and Hour Division, and
(1) Preserve a copy as part of the records,
(2) Deliver a copy to the employee, and
(3) File the original, as evidence of payment by the contractor and receipt by the employee, with the Administrator within 10 business days after payment is made.