California Code, Code of Civil Procedure - CCP § 1908

(a) The effect of a judgment or final order in an action or special proceeding before a court or judge of this state, or of the United States, having jurisdiction to pronounce the judgment or order, is as follows:

(b) A person who is not a party but who controls an action, individually or in cooperation with others, is bound by the adjudications of litigated matters as if he were a party if he has a proprietary or financial interest in the judgment or in the determination of a question of fact or of a question of law with reference to the same subject matter or transaction; if the other party has notice of his participation, the other party is equally bound.

At any time prior to a final judgment, as defined in Section 577, a determination of whether the judgment, verdict upon which it was entered, or a finding upon which it was entered is to be binding upon a nonparty pursuant to this subdivision or whether such nonparty is entitled to the benefit of this subdivision may, on the noticed motion of any party or any nonparty that may be affected by this subdivision, be made in the court in which the action was tried or in which the action is pending on appeal. If no such motion is made before the judgment becomes final, the determination may be made in a separate action. If appropriate, a judgment may be entered or ordered to be entered pursuant to such determination.