Can the optimal tariff be zero for a large country?: Reconsideration from a dynamic viewpoint

2022 Fiscal Year Final Research Report

• Project/Area Number: 19K01662
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 07040:Economic policy-related
• Research Institution: Waseda University
• Principal Investigator: Naito Takumi 早稲田大学, 政治経済学術院, 教授 (80314350)
• Project Period (FY): 2019-04-01 – 2023-03-31
• Keywords: 最適関税

Outline of Final Research Achievements

The purpose of this paper is to theoretically clarify whether and when the optimal tariff can be zero for a large country. In particular, I reconsider the optimal tariff for a large country from a dynamic viewpoint. I incorporate import tariffs and tariff revenues into either R&D-based or capital accumulation-based growth models with firm heterogeneity and cross-country asymmetry, characterize the optimal tariff, and compare it across the two models.

In the R&D-based model, the optimal tariff can be zero for a large country. In the capital accumulation-based model, although the optimal tariff cannot be zero for a large country, a more productive (and hence an economically larger) country sets a lower optimal tariff.

Free Research Field

国際経済学

Academic Significance and Societal Importance of the Research Achievements

2018年米中間で起こったような，各国がお互いに正の最適関税を掛け合う「貿易戦争」は，世界的な自由貿易に比べて全ての国の厚生を低める，いわば囚人のジレンマをもたらす．従来の国際貿易論における大国にとって最適関税が正となるという結果が，その理論的な根拠であった．

本研究では，関税引き上げが経済成長率を低めるという動学的視点を導入すると，大国にとって最適関税はゼロとなり得ることを示した．これは，各国が自発的に（相互性に依存せずに）自由貿易を選択するための強い根拠をもたらす．