Cal. Pub. Util. Code § 120108

The board shall maintain accounting records and shall report accounting transactions in accordance with generally accepted accounting principles as adopted by the Government Accounting Standards Board (GASB) of the Financial Accounting Foundation for both public reporting purposes and for reporting of activities to the Controller. The activities of any nonprofit corporation or other legal entity wholly owned or controlled by the board and operating a public transit system shall be reported separately in the board’s annual report to the Controller.