Cal. Rev. & Tax. Code § 13107

In any judgment, interest shall be allowed, subject to the same limitations as are prescribed by Section 12984, at the modified adjusted rate per annum established pursuant to Section 6591.5, upon the amount found to have been illegally collected from the date of payment of the amount to the date of allowance of credit on account of the judgment or to a date preceding the date of the refund warrant by not more than 30 days, the date to be determined by the Controller.