On July 24, 2013, the Massachusetts Legislature passed the Transportation Finance Bill (H.B. 3535) over Governor Patrick’s veto, implementing three key changes to Massachusetts’ state tax system. To begin, the new legislation requires the use of a market-based sourcing method for sales of intangibles in computing the sales factor of a taxpayer’s apportionment formula for corporate excise tax purposes. The new law also expands Massachusetts’ sales and use tax base to include “computer system design services,” defined as “the planning, consulting, or designing of computer systems that integrate computer hardware, software, or communication technologies and are provided by a vendor or a third party.”  Finally, the legislation amends the statutory definition of taxable “services” to include “the modification, integration, enhancement, installation or configuration of standardized software” and to exclude “data access, data processing or information management services.” The legislative changes are effective July 31, 2013. Mass. St. 2013 c. 46; Mass. G.L. c. 63 § 38(f), c. 64H § 1. On July 25, 2013, the Massachusetts Department of Revenue issued a Technical Information Release to provide initial guidance on the application of the sales and use tax to computer system design and software modification services, including applicable sourcing rules and transition rules for existing service contracts. Mass. TIR 13-10, Sales and Use Tax on Computer and Software Services Law Changes Effective July 31, 2013 (July 25, 2013).