有效税率、企业规模与全球最低税

This paper studies how tax expenditures shape the distribution of firm-level effective tax rates and their implications for domestic minimum taxes under the global minimum tax (GMT). Using administrative corporate tax returns from 16 countries, we document that tax expenditures are large and that effective tax rates tend to follow a hump-shaped pattern across the firm-size distribution, with particularly low rates among the largest firms. As a result, more than one quarter of the largest firms have effective tax rates below the 15-percent GMT rate, despite substantially higher statutory rates. However, firm-level simulations from five countries with data on subsidiaries of multinationals suggest that GMT-consistent domestic minimum taxes would likely generate modest revenue gains—a few percentage points of baseline CIT revenue—reflecting the small number of firms in scope and extensive deductions.