California Code, Revenue and Taxation Code - RTC § 23311

(a) If a qualified entity, as defined by Section 23310, has been dissolved or canceled as described by Section 23310, but continues to do business within the meaning of subdivision (a) of Section 23101, or has any remaining assets which were not disclosed by the qualified entity at the time of request for abatement under Section 23310, the total tax, interest, and penalties that were abated pursuant to Section 23310 shall be immediately due and payable. In addition, a penalty in an amount equal to 50 percent of the total tax abated pursuant to Section 23310, plus accrued interest payable pursuant to Section 19101 on that amount for the period or periods beginning on the last date prescribed by law for the payment of that tax, determined without regard to extensions, and ending on the date the tax was abated, shall be imposed.

(b) The penalty imposed by this section is in addition to any other penalty imposed under Part 10 (commencing with Section 17001), Part 10.2 (commencing with Section 18401) and Part 11 (commencing with Section 23001).

(c) Article 3 (commencing with Section 19031) of Chapter 4 of Part 10.2, relating to deficiency assessments, shall not apply with respect to the assessment or collection of any penalty imposed by subdivision (a) or to previously abated tax, interest, and penalties that are due and payable pursuant to this section.