In case the entire business of any corporation is not transacted within the city, the tax or taxes authorized or imposed under this act shall be based upon that portion of the net income of a corporation for the tax year as may be determined by allocations and apportionments made as follows:
The amount assignable to the city of expenditures of the corporation for wages, salaries, commissions, or other compensation of its employes, shall be such expenditures for the taxable year as represents the wages, salaries, commissions, or other compensation of employes not chiefly situated at, connected with, or sent out from, premises for the transaction of business maintained by the corporation outside the city.
In cases where only two of the foregoing three rules are applicable, the remainder of the net income of the corporation shall be divided into two equal parts instead of three, each of which shall be apportioned in accordance with one of the remaining two rules. If only one of the three rules is applicable, the part of the net income received from business carried on within the city shall be determined solely by that rule.
A rule shall not be deemed to be inapplicable merely because all the tangible property or the expenditures of a corporation for wages, salaries, commissions, or other compensation, or the gross receipts of the corporation are found to be situated, incurred or received without the city.
If the allocation and apportionment provisions of this section do not fairly represent the extent of the taxpayer's business activity in the city, the taxpayer may petition for, in respect to all or any part of the taxpayer's business activity, if reasonable: separate accounting; the exclusion of any one or more of the factors; the inclusion of one or more additional factors which will fairly represent the taxpayer's business activity in the city; or the employment of any other method to effectuate an equitable allocation and apportionment of the taxpayer's income.
The ordinance authorizing or imposing a tax hereunder may create additional exclusions, allocations or exemptions and may provide for a reasonable limitation on the period within which actions to collect the tax may be instituted.
53 P.S. § 16116