California Code, Revenue and Taxation Code - RTC § 18622

(a) If any item required to be shown on a federal tax return, including any gross income, deduction, penalty, credit, or tax for any year of any taxpayer is changed or corrected by the Commissioner of Internal Revenue or other officer of the United States or other competent authority, or where a renegotiation of a contract or subcontract with the United States results in a change in gross income or deductions, that taxpayer shall report each change or correction, or the results of the renegotiation, within six months after the date of each final federal determination of the change or correction or renegotiation, or as required by the Franchise Tax Board, and shall concede the accuracy of the determination or state wherein it is erroneous.For any individual subject to tax under Part 10 (commencing with Section 17001), changes or corrections need not be reported unless they increase the amount of tax payable under Part 10 (commencing with Section 17001) for any year.

(b) Any taxpayer filing an amended return with the Commissioner of Internal Revenue shall also file within six months thereafter an amended return with the Franchise Tax Board which shall contain any information as it shall require.For any individual subject to tax under Part 10 (commencing with Section 17001), an amended return need not be filed unless the change therein would increase the amount of tax payable under Part 10 (commencing with Section 17001) for any year.

(c) Notification of a change or correction by the Commissioner of Internal Revenue or other officer of the United States or other competent authority, or renegotiation of a contract or subcontract with the United States that results in a change in any item or the filing of an amended return must be sufficiently detailed to allow computation of the resulting California tax change and shall be reported in the form and manner as prescribed by the Franchise Tax Board.

(d) For purposes of this part, the date of each final federal determination shall be the date on which each adjustment or resolution resulting from an Internal Revenue Service examination is assessed pursuant to Section 6203 of the Internal Revenue Code. 1