Cal. Unemp. Ins. Code § 1057
Upon dissolution of a joint venture each participating employer may within 90 days apply for the transfer of his proportionate share of the reserve account. Upon receipt of the application the separate account, actual contribution and benefit experience and pay rolls of such joint venture shall be apportioned among the employers making such application in the same proportion that assets are distributed among the participating employers, and the portion thereof of each shall be transferred to each such employer for the purpose of determining its rate of contribution after the dissolution with the same effect for such purpose as if the applicable portion of the operations of such joint venture had at all times been carried on by such employer. Such portion of such separate account shall be transferred by the director to each such employer and as of the date of such dissolution shall become the separate account or part of the separate account, as the case may be, of such employer. The benefits thereafter chargeable to such joint venture on account of employment relating to such joint venture prior to the date of such dissolution shall be charged to the separate accounts of such employers in proportion to their participation in the joint venture. Any such joint venture shall promptly notify the director of its dissolution.
As used in this section only, "employer" includes the successor of an employer and any subsequent successor employer or employers.
Ca. Unemp. Ins. Code § 1057