Over the past several decades, state corporate income taxes have declined markedly. One of the factors contributing to this decline has been aggressive tax avoidance on the part of large, multi-state corporations, costing states billions of dollars. The most effective approach to combating corporate tax avoidance is combined reporting, a method of taxation currently employed in more than half of the states that tax corporate income. The two most recent states to enact combined reporting are Rhode Island in 2014 and Connecticut in 2015.
In several states, including Connecticut, Illinois, Massachusetts, Rhode Island, and Vermont, lawmakers adopted the policy after first carrying out in-depth studies of its potential effects. This policy brief explains how combined reporting works.