5 CFR § 351.502 - Order of retention - excepted service.
(a) Competing employees shall be classified on a retention register in tenure groups on the basis of their tenure of employment, veteran preference, length of service, and performance in descending order as set forth under § 351.501(a) for competing employees in the competitive service.
(b) Groups are defined as follows:
(1) Group I includes each permanent employee whose appointment carries no restriction or condition such as conditional, indefinite, specific time limit, or trial period.
(2) Group II includes each employee:
(i) Serving a trial period; or
(ii) Whose tenure is equivalent to a career-conditional appointment in the competitive service in agencies having such excepted appointments.
(3) Group III includes each employee:
(i) Whose tenure is indefinite (i.e., without specific time limit), but not actually or potentially permanent;
(ii) Whose appointment has a specific time limitation of more than 1 year; or
(iii) Who is currently employed under a temporary appointment limited to 1 year or less, but who has completed 1 year of current continuous service under a temporary appointment with no break in service of 1 workday or more.