830 CMR 63.38.1: Apportionment of Income explains the apportionment rules that are to be used by corporations to determine their Massachusetts income tax liability. The apportionment rules are intended to determine what percentage of a corporation’s income is attributable to Massachusetts for purposes of taxation. The regulation explains the three “factors” that determine a corporation’s apportionment formula. These three factors pertain to a corporation’s in-state property, payroll, and sales. The new regulation promulgated on 1/2/15 includes the implementation of the market-based sourcing principles adopted pursuant to St. 2013, c. 46, § 37, pertaining to the sales factor apportionment of sales of other than tangible personal property. The regulation provides specific market-based sourcing rules for (1) the sale, rental, lease or license of real property, (2) the rental, lease or license of tangible personal property, (3) the sale of a service, (4) the license or lease of intangible property, and (5) the sale of intangible property.