Cal. INS § 1064.5

(a) In a delinquency proceeding in a reciprocal state against an insurer domiciled in that state, claimants against such insurer who reside within this state may file claims either with the ancillary receiver, if any, appointed in this state, or with the domiciliary receiver. All such claims shall be filed on or before the last date fixed for the filing of claims in the domiciliary delinquency proceeding.

(b) Controverted claims belonging to claimants residing in this state may either (1) be proved in the domiciliary state as provided by the laws of that state, or (2), if ancillary proceedings have been commenced in this state, be proved in those proceedings. In the event that any such claimant elects to prove his or her claim in this state, he or she shall file his or her claim with the ancillary receiver in the manner provided by the law of this state for the proving of claims against insurers domiciled in this state, and he or she shall give notice in writing to the receiver in the domiciliary state, either by registered mail or by personal service at least 40 days prior to the date set for hearing. The notice shall contain a concise statement of the amount of the claim, the facts on which the claim is based, and the priorities asserted, if any. If the domiciliary receiver, within 30 days after the giving of notice, shall give notice in writing to the ancillary receiver and to the claimant, either by registered mail or by personal service, of his or her intention to contest that claim, he or she shall be entitled to appear or to be represented in any proceeding in this state involving the adjudication of the claim. The final allowance of the claim by the courts of this state shall be accepted as conclusive as to its amount, and shall also be accepted as conclusive as to its priority, if any, against special deposits or other security located within this state.