California Code, Public Utilities Code - PUC § 583

(a) No information furnished to the commission by a public utility, a business that is a subsidiary or affiliate of a public utility, or a corporation that holds a controlling interest in a public utility, except those matters specifically required to be open to public inspection by this part, shall be open to public inspection or made public, except on order of the commission or by the commission or a commissioner in the course of a hearing or proceeding.A present or former officer or employee of the commission who divulges that information is guilty of a misdemeanor.

(b) Notwithstanding subdivision (a) or any other law, a present officer or employee of the commission may share information with the Independent System Operator pursuant to an agreement to treat the shared information as confidential.