California Code, Public Utilities Code - PUC § 980

(a) “Core gas customer” has the same meaning as that specified in the tariff of the gas corporation whose territory the customer in question lies within.  A core small commercial customer account that is associated with and part of the same business operation as a noncore large commercial customer account is not a “core gas customer” for purposes of this chapter.

(b) “Core transport agent” means an entity that offers core gas procurement service to customers within the service territory of a gas corporation, but does not include a gas corporation, and does not include a public agency that offers gas service to core and noncore gas customers within its jurisdiction, or within the service territory of a local publicly owned gas utility.  “Core transport agent” includes the unregulated affiliates and subsidiaries of a gas corporation.

(c) “Gas corporation” has the same meaning as that set forth in Section 222.