Cal. Rev. & Tax. Code § 25128

(a) Notwithstanding Section 38006, for taxable years beginning before January 1, 2013, all business income shall be apportioned to this state by multiplying the business income by a fraction, the numerator of which is the property factor plus the payroll factor plus twice the sales factor, and the denominator of which is four, except as provided in subdivision (b) or (c).
(b) If an apportioning trade or business derives more than 50 percent of its “gross business receipts” from conducting one or more qualified business activities, all business income of the apportioning trade or business shall be apportioned to this state by multiplying business income by a fraction, the numerator of which is the property factor plus the payroll factor plus the sales factor, and the denominator of which is three.
(c) For purposes of this section, a “qualified business activity” means the following:
1. (1) For taxable years beginning before January 1, 2025:
  1. (A) An agricultural business activity.
  2. (B) An extractive business activity.
  3. (C) A savings and loan activity.
  4. (D) A banking or financial business activity.
2. (2) For taxable years beginning on or after January 1, 2025:
  1. (A) An agricultural business activity.
  2. (B) An extractive business activity.
(d) For purposes of this section:
1. (1) “Gross business receipts” means gross receipts described in subdivision (e) or (f) of Section 25120, other than gross receipts from sales or other transactions within an apportioning trade or business between members of a group of corporations whose income and apportionment factors are required to be included in a combined report under Section 25101, limited, if applicable, by Section 25110, whether or not the receipts are excluded from the sales factor by operation of Section 25137.
2. (2) “Agricultural business activity” means activities relating to any stock, dairy, poultry, fruit, furbearing animal, or truck farm, plantation, ranch, nursery, or range. “Agricultural business activity” also includes activities relating to cultivating the soil or raising or harvesting any agricultural or horticultural commodity, including, but not limited to, the raising, shearing, feeding, caring for, training, or management of animals on a farm as well as the handling, drying, packing, grading, or storing on a farm any agricultural or horticultural commodity in its unmanufactured state, but only if the owner, tenant, or operator of the farm regularly produces more than one-half of the commodity so treated.
3. (3) “Extractive business activity” means activities relating to the production, refining, or processing of oil, natural gas, or mineral ore.
4. (4) “Savings and loan activity” means any activities performed by savings and loan associations or savings banks that have been chartered by federal or state law.
5. (5) “Banking or financial business activity” means activities attributable to dealings in money or moneyed capital in substantial competition with the business of national banks.
6. (6) “Apportioning trade or business” means a distinct trade or business whose business income is required to be apportioned under Sections 25101 and 25120, limited, if applicable, by Section 25110, using the same denominator for each of the applicable payroll, property, and sales factors.
7. (7) Paragraph (4) of subdivision (c) shall apply only if the Franchise Tax Board adopts the Proposed Multistate Tax Commission Formula for the Uniform Apportionment of Net Income from Financial Institutions, or its substantial equivalent, and shall become operative upon the same operative date as the adopted formula.
8. (8) In any case where the income and apportionment factors of two or more savings associations or corporations are required to be included in a combined report under Section 25101, limited, if applicable, by Section 25110, both of the following shall apply:
  1. (A) The application of the more than 50 percent test of subdivision (b) shall be made with respect to the “gross business receipts” of the entire apportioning trade or business of the group.
  2. (B) The entire business income of the group shall be apportioned in accordance with either subdivision (a) or (b), or Section 25128.7, as applicable.