On March 31, 2014, New York Governor Andrew Cuomo signed into law S.B. 6359-D, A 8559-D, (Chapter 59), enacting significant changes to New York State’s corporate tax regime, most of which take effect for the 2015 tax year. One of the more notable changes is the state’s adoption of mandatory unitary combined reporting, which replaces required combination based on the existence of substantial intercorporate transactions. The substantial intercorporate transaction provisions were effective starting in 2007 and replaced the state’s previous rules that required or permitted combination by commonly owned corporations only when the corporations engaged in a unitary business and combined filing was necessary to prevent distortion. This Insight highlights changes made to the state’s combined reporting system.