Cal. RTC § 19021

In the case of taxpayers subject to the tax imposed by Article 3 (commencing with Section 23181) of Chapter 2 of Part 11, there shall be due and payable on or before the 15th day of the third month following the close of the preceding year from each taxpayer a percentage of its net income as disclosed by its return which is equal to the rate applicable to corporations subject to the tax imposed by Article 2 (commencing with Section 23151) of Chapter 2 of Part 11 plus the personal property tax rate equivalent included in the bank and financial corporation tax rate determination by the Franchise Tax Board pursuant to Sections 23186 and 23186.1. The payment required by this section shall not be less than the minimum tax specified in Section 23153.