48 CFR §4.1800

1. (a)This subpart prescribes policies and procedures for identification of commercial and government entities. The Commercial and Government Entity (CAGE) code system may be used, among other things, to—
   1. (1)Exchange data with another contracting activity, including contract administration activities and contract payment activities;
   2. (2)Exchange data with another system that requires the unique identification of a contractor entity; or
   3. (3)Identify when offerors are owned or controlled by another entity.
2. (b)For information on the unique entity identifier, which is a different identifier, see 4.605 and the provisions at 52.204-6, Unique Entity Identifier, and 52.204-7, System for Award Management.