A Proposal to Adopt Formulary Apportionment for Corporate Income Taxation: The Hamilton Project

56 Pages Posted: 25 Jun 2007

See all articles by Reuven S. Avi-Yonah

Reuven S. Avi-Yonah

University of Michigan Law School

Kimberly A. Clausing

UCLA School of Law; Peterson Institute for International Economics

Date Written: April 2007


The current system of taxing the income of multinational firms in the United States is flawed across multiple dimensions. The system provides an artificial tax incentive to earn income in low-tax countries, rewards aggressive tax planning, and is not compatible with any common metrics of efficiency. The U.S. system is also notoriously complex; observers are nearly unanimous in lamenting the heavy compliance burdens and the impracticality of coherent enforcement. Further, despite a corporate tax rate one standard deviation above that of other OECD countries, the U.S. corporate tax system raises relatively little revenue, due in part to the shifting of income outside the U.S. tax base.

In this proposal, we advocate moving to a system of formulary apportionment for taxing the corporate income of multinational firms. Under our proposal, the U.S. tax base for multinational corporations would be calculated based on a fraction of their worldwide income. This fraction would simply be the share of their worldwide sales that occur in the United States. This system is similar to the current method that U.S. states use to allocate national income across states. The state system arose due to the widespread belief that it was impractical to account separately for what income is earned in each state when states are highly integrated economically. Similarly, in an increasingly global world economy, it is difficult to assign profits to individual countries, and attempts to do so are fraught with opportunities for tax avoidance.

Under our proposed formulary apportionment system, firms would no longer have an artificial tax incentive to shift income to low-tax locations. This would help protect the U.S. tax base while reducing the distortionary features of the current tax system. In addition, the complexity and administrative burden of the system would be reduced. The proposed system would be both better suited to an integrated world economy and more compatible with the tax policy goals of efficiency, equity, and simplicity.

Keywords: transfer pricing, formulary apportionment

JEL Classification: H25, H26

Suggested Citation

Avi-Yonah, Reuven S. and Clausing, Kimberly A., A Proposal to Adopt Formulary Apportionment for Corporate Income Taxation: The Hamilton Project (April 2007). U of Michigan Law & Economics, Olin Working Paper No. 07-009, U of Michigan Public Law Working Paper No. 85, Available at SSRN: https://ssrn.com/abstract=995202 or http://dx.doi.org/10.2139/ssrn.995202

Reuven S. Avi-Yonah (Contact Author)

University of Michigan Law School ( email )

625 South State Street
Ann Arbor, MI 48109-1215
United States
734-647-4033 (Phone)

Kimberly A. Clausing

UCLA School of Law ( email )

385 Charles E. Young Drive East
Los Angeles, CA 90095-0001
United States

HOME PAGE: http://law.ucla.edu/faculty/faculty-profiles/kimberly-clausing

Peterson Institute for International Economics ( email )

1750 Massachusetts Avenue, NW
Washington, DC 20036
United States

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