5 C.F.R. § 575.305
Applicability to employees
(a) An agency may pay a retention incentive to an individual employee under the conditions prescribed in this subpart when the agency determines that—
(1) The unusually high or unique qualifications (i.e., competencies) of the employee or a special need of the agency for the employee's services makes it essential to retain the employee; and
(2) The employee would be likely to leave the Federal service in the absence of a retention incentive.
(b) Except as provided in paragraph (c) of this section, an agency may pay a retention incentive to a group or category of employees under the conditions prescribed in this subpart when the agency determines that—
(1) The unusually high or unique qualifications (i.e., competencies) of the group or category of employees or a special need of the agency for the employees' services makes it essential to retain the employees in that group or category; and
(2) There is a high risk that a significant number of the employees in the group would be likely to leave the Federal service in the absence of a retention incentive.
(c) An agency may not include in a group retention incentive authorization an employee covered by § 575.303(a)(2), (a)(3), or (a)(5) or those in similar categories of positions approved by OPM to receive retention incentives under § 575.303(a)(7).
(d) A retention incentive may be paid only when the employee's rating of record (or an official performance appraisal or evaluation under a system not covered by 5 U.S.C. chapter 43 or 5 CFR part 430) is at least “Fully Successful” or equivalent.