Cal. Unemp. Ins. Code § 3254.5
A voluntary plan in force and effect at the time a successor employing unit acquires the organization, trade, or business, or substantially all the assets thereof, or a distinct and severable portion of the organization, trade, or business, and continues its operation without substantial reduction of personnel resulting from the acquisition, shall not withdraw without specific request for withdrawal thereof. The successor employing unit and the insurer shall be deemed to have consented to the provisions of the plan unless written request for withdrawal, effective as of the date of acquisition, is transmitted to the Director of Employment Development, by the employer or the insurer, within 30 days after the acquisition date, or within 30 days after notification from the Director of Employment Development that the plan is to continue, whichever is later. Unless the plan is withdrawn as of the date of acquisition by the successor employer or the insurer, a written request for withdrawal shall be effective only on the anniversary of the effective date of the plan next occurring on or after the date of acquisition, except that the plan may be withdrawn on the operative date of any law increasing the benefit amounts provided by Sections 2653 and 2655 or the operative date of any change in the rate of worker contributions as determined by Section 984, if notice of the withdrawal of the plan is transmitted to the Director of Employment Development not less than 30 days prior to the operative date of law or change. If the plan is not withdrawn on 30 days' notice because of the enactment of a law increasing benefits or because of a change in the rate of worker contributions as determined by Section 984, the plan shall be amended to conform to the increase or change on the operative date of the increase or change. Promptly, upon notice of change in ownership, any insurer of a plan shall prepare and issue policy forms and amendments as required, unless the plan is withdrawn. Nothing contained in this section shall prevent future withdrawal of any plans on an anniversary of the effective date of the plan upon 30 days' notice, except that the plan may be withdrawn on the operative date of any law increasing the benefit amounts provided by Sections 2653 and 2655 or the operative date of any change in the rate of worker contributions as determined by Section 984, if notice of the withdrawal of the plan is transmitted to the Director of Employment Development not less than 30 days prior to the operative date of the law or change. If the plan is not withdrawn on 30 days' notice because of the enactment of a law increasing benefits or because of a change in the rate of worker contributions as determined by Section 984, the plan shall be amended to conform to the increase or change on the operative date of the increase or change.
Ca. Unemp. Ins. Code § 3254.5