Cal. Ins. Code § 1392
Except as provided by Sections 1397, 1398, 1400 and 1401, every subscriber of an exchange subject to this article shall be liable to pay, and shall pay, his proportionate part of any such assessment, in accordance with law and his contract covering any such deficiency assessment (a) if he is notified by either the attorney or the commissioner of intention to levy such assessment within one year after the expiration or cancellation of his policy, or, (b) if an order appointing a conservator or liquidator of such exchange is entered, within one year after such expiration or cancellation.
The period to be covered by the assessment shall be the period of one year immediately preceding (a) the date of notification by either the attorney or the commissioner of the intention to levy such assessment, or, (b) the date of entry of an order appointing a conservator or liquidator of such exchange, as the case may require.
Ca. Ins. Code § 1392