Cal. RTC § 6480.7

(a) The board may require any supplier or wholesaler subject to this article to place with the board any security that the board determines is necessary to ensure compliance with this article. The amount of the security shall be fixed by the board but shall not be greater than three times the estimated average liability of suppliers or wholesalers required to file returns for monthly periods, determined in any manner that the board deems proper, or five hundred thousand dollars ($500,000), whichever amount is less. These amounts apply regardless of the type of security placed with the board. The amount of the security may be increased or decreased by the board subject to the maximum amounts. The security required pursuant to this section is in addition to the bond or bonds required pursuant to Section 7486.

(b) The board may sell the security at public auction if it becomes necessary to so do in order to recover any tax or any amount required to be collected or penalty due. Notice of the sale may be served upon the person who placed the security personally or by mail. If service is by mail, service shall be made in the manner prescribed for service of a notice of a deficiency determination and shall be addressed to the person at his or her address as it appears in the records of the board. However, security in the form of a bearer bond issued by the United States or the State of California which has a prevailing market price may be sold by the board at a private sale at a price not lower than the prevailing market price thereof. Upon any sale, any surplus above the amounts due shall be returned to the supplier or wholesaler who placed the security.