States who have recently adopted market-based sourcing have similar guidelines. The goal is to develop uniformity for current and future states that enact market-based sourcing for determining the sourcing of sales of services, intangible property and other non-tangible personal property for multistate income tax apportionment purposes.
The Working Draft provides insight into where the MTC is going and how complicated market-based sourcing really is. The support for switching to market-based sourcing from the costs-of-performance method is partially based on the claim that it is easier to implement. I think the 44-page document speaks for itself.