Cal. UIC § 1731

Any person or employing unit that acquires the organization, trade or business, or substantially all the assets thereof, of an employer shall withhold in trust money or other property sufficient in amount or value to cover the amount of any contributions, interest and penalties due or unpaid from such employer until such employer produces a certificate from the department stating that no contributions, interest or penalties are due. If such employer does not produce such certificate, the acquiring person or employing unit shall pay the amount or the value of the property so withheld to the department at the time of such acquisition.