Revenue and Taxation Code – RTC § 32271
If the board is dissatisfied with the return or returns filed or amount of tax paid to the state by any taxpayer, it may compute and determine the amount to be paid based upon any information available to it. One or more additional determinations may be made of the amount of tax due for one or for more than one period. The amount of tax so determined shall bear interest at the modified adjusted rate per month, or fraction thereof, established pursuant to Section 6591.5 , from the 15th day after the close of the period for which the amount of the tax, or any portion thereof, should have been reported until the date of payment. In making a determination, the board may offset overpayment for a period or periods against underpayments for another period or periods and against the interest and penalties on the underpayments. If any part of the deficiency for which a determination of an additional amount due is made is found to have been occasioned by negligence or intentional disregard of this part or authorized rules, a penalty of 10 percent of the amount of the determination shall be added, plus interest as above provided. If any part of the deficiency for which a determination of an additional amount due is made is found to be occasioned by fraud or an intent to evade this part or authorized rules, a penalty of 25 percent of the amount of the determination shall be added, plus interest as above provided. The board shall give to the taxpayer written notice of its determination. The notice shall be placed in a sealed envelope, with postage paid, addressed to the taxpayer at his address as it appears in the records of the board. The giving of notice shall be deemed complete at the time of the deposit of the notice in the United States Post Office, or a mailbox, sub-post office, substation or mail chute or other facility regularly maintained or provided by the United States Postal Service without extension of time for any reason. In lieu of mailing, a notice may be served personally by delivering to the person to be served and service shall be deemed complete at the time of delivery. Personal service to a corporation may be made by delivery of a notice to any person designated in the Code of Civil Procedure to be served for the corporation with summons and complaint in a civil action.