California Code, Revenue and Taxation Code - RTC § 45451

(1) For amounts disclosed on a report received by the board before the date the return is delinquent, the date the amount would have been due and payable.

(2) For amounts disclosed on a report filed on or after the date the return is delinquent, the date the return is received by the board or the year following the fee due date pursuant to Section 45151, whichever is later.

(3) For amounts determined under Section 45351, pertaining to jeopardy assessments, the date the notice of the board's finding is mailed or issued.

(4) For all other amounts, the date the assessment is final.