California Code, Revenue and Taxation Code - RTC § 19545

(a) The taxpayer is a party to the proceeding, or the proceeding arose out of, or in connection with, determining the taxpayer's civil or criminal liability, or the collection of the taxpayer's civil liability with respect to any tax imposed under this part.

(b) The treatment of an item reflected on the return is directly related to the resolution of an issue in the proceeding.

(c) The return or return information directly relates to a transactional relationship between a person who is a party to the proceeding and the taxpayer which directly affects the resolution of an issue in the proceeding.