To constrain the use of intangible assets in tax-motivated state income shifting, many U.S. state governments adopted addback statutes. Addback statutes reduce the tax benefits that firms can gain from creating intangible assets such as patents. Using a sample of U.S. public firms, we examine the effect of addback statutes on corporate innovation behavior. First, the adoption of addback statutes leads to a 4.77 percentage point decrease in the number of patents and a 5.12 percentage point decrease in the number of patent citations. Second, the “disappearing patents” resulting from addback statutes have significant economic value. Third, after a state adopts an addback statute, a firm with material subsidiaries in that state assigns fewer patents to subsidiaries in zero-tax states, whereas the number of patents assigned to the other states does not change. Overall, our findings suggest that addback statutes impede corporate innovation.

为了限制无形资产在税收驱动的州收入转移中的使用，许多美国州政府采用了加法法。回加法减少了企业从创造专利等无形资产中获得的税收利益。我们使用美国上市公司的样本，研究了加法法规对公司创新行为的影响。首先，采用加成法会导致专利数量减少4.77个百分点，专利被引用数量减少5.12个百分点。其次，因增加法规而产生的“消失的专利”具有重大的经济价值。第三，在州采用加法规约后，在该州拥有重要子公司的公司向处于零税率状态的子公司分配的专利数量较少，而分配给其他州的专利数量没有变化。总体而言，我们的发现表明加法会阻碍企业创新。