Section 12978 Of Article 2. Refund Or Credit For Collected Taxes From California Revenue And Taxation Code >> Division 2. >> Part 7. >> Chapter 7. >> Article 2.

. No credit or refund shall be allowed or approved after four years after April 1st of the year following the year for which the overpayment was made, or with respect to a deficiency assessment made under Article 3 (commencing with Section 12421) of Chapter 4 after six months from the date the deficiency assessment becomes final, or after six months from the date of the overpayment, whichever period expires the later, unless a claim therefor is filed with the commissioner or the board within that period.