In the taxation of income which is subject to City income tax if the books and records of a taxpayer conducting a business or profession both within and without the boundaries of the City shall disclose with reasonable accuracy what portion of its net profit is attributable to that part of the business or profession conducted within the boundaries of the City, then only such portion shall be considered as having a taxable situs in the City for the purposes of municipal income taxation. The portion of the entire net profits of a taxpayer to be allocated as having been derived from within the City in the absence of actual records thereof, shall be determined as follows: Multiply the entire net profits by a business allocation percentage to be determined by a three factor formula of property, payroll, and sales, each of which shall be given equal weight, as follows:
(a) The average net book value of the real and tangible personal property owned or used by the taxpayer in the business or profession in the City during the taxable period to the average net book value of all the real and tangible personal property owned or used by the taxpayer in the business or profession during the same period, wherever situated. As used in the preceding paragraph, real property shall include property rented or leased by the taxpayer and the value of such property shall be determined by multiplying the annual rental thereon by eight.
(b) Salaries, wages, commissions, other compensation and other income paid during the taxable period to persons employed in the business or profession for services performed in the City to salaries, wages, commissions, other compensation and other income paid during the same period to persons employed in the business or profession, wherever their services are performed.
(c) Gross receipts of the business or profession from sales made and services performed during the taxable period in the City to gross receipts of the business or profession during the same period from sales and services, wherever made or performed. In the event that the foregoing allocation formula does not produce an equitable result, another basis may, under uniform regulations, be substituted so as to produce such result.
(1969 Code 92.05)