Cal. RTC § 19043.5

(a) (1) If the Franchise Tax Board determines that the amount of a carryover disclosed by the taxpayer on an original or amended return, including an amended return reporting federal adjustments pursuant to Section 18622, is more than the amount of the carryover disclosed by its own examination, it may mail a notice or notices to the taxpayer of the proposed carryover adjustment and the proposed adjusted carryover amount.

(2) For purposes of this section, “carryover” means the amount of a credit, loss, deduction, or other item that is shown on an original or amended return for carry forward to a subsequent taxable year.

(b) Except as otherwise provided in this section, the provisions of this article applicable to a proposed deficiency assessment shall be applicable to a proposed adjusted carryover amount, including protest and appeal rights as if that proposed adjusted carryover amount were a proposed deficiency assessment.

(c) (1) A proposed adjusted carryover amount shall become a final adjusted carryover amount under this section following a determination of the board regarding that proposed adjusted carryover amount that becomes final pursuant to the provisions of Section 19048.

(2) A final adjusted carryover amount shall be binding and conclusive with respect to the amount of that carryover for purposes of Part 10 (commencing with Section 17001), this part, and Part 11 (commencing with Section 23001), except in the following circumstances:

(A) In the event of fraud, malfeasance, or misrepresentation of a material fact.

(B) Subject to any provision of the Revenue and Taxation Code that expressly provides that effect be given to that provision notwithstanding any other law or rule of law.

(C) Subject to any law that is, or becomes, operative with respect to a taxable year affected by the final adjusted carryover amount.

(D) Subject to any final federal adjustment that is made with respect to the taxpayer’s federal income tax liability for a taxable year affected by the final adjusted carryover amount.

(E) In an action brought pursuant to provisions of Section 19382.

(d) (1) In any case where there is a final adjusted carryover amount with respect to a carryover, the taxpayer shall report that final adjusted carryover amount on an original or amended return for any subsequent year.

(2) If a taxpayer fails to comply with paragraph (1), then any adjustment required to make the amount of the carryover shown on the return for any year consistent with the final adjusted carryover amount shall be treated as arising out of a mathematical error and assessed and collected under Section 19051.

(e) Except as provided in subdivision (c), this section shall not affect the determination, issuance, assessment, collection, or validity of a deficiency assessment under this part.