5 CFR § 575.308 - Approval criteria and written determination.
(a) An agency in its sole and exclusive discretion, subject only to OPM review and oversight, may approve a retention incentive for an individual employee or group or category of employees using the approval criteria in § 575.306.
(b) For each determination to pay a retention incentive under this subpart, an agency must document in writing -
(1) The basis for determining that the unusually high or unique qualifications of the employee (or group of employees) or a special need of the agency for the employee's (or group of employees') services makes it essential to retain the employee(s);
(3) The basis for establishing the amount and timing of the approved retention incentive payment and the length of the required service period.