Cal. Rev. & Tax. Code § 8951

The department, whenever it deems it necessary to ensure compliance with this part or any rule or regulation adopted under this part, may require any user or vendor to deposit with it any security that it may determine. Any security in the form of cash, government bonds, or insured deposits in banks and savings and loan institutions shall be held by the department in trust to be used solely in the manner provided for by this section and Section 8956. The department may sell the security at public sale if it becomes necessary in order to recover any amount due under this part. Notice of the sale may be served upon the person who deposited the security in the manner prescribed for service of notice of a deficiency determination. Upon any sale, any surplus above the amount due shall be returned to the person who deposited the security.