タカハシ　トモヤ   Takahashi,Tomoya   高橋　知也    所属   経済学部 経済学科    職種   教授
言語種別	英語
発行・発表の年月	2026/03
形態種別	学術雑誌
標題	Tariffs on Vertically Differentiated Platforms in Two-Sided Markets
執筆形態	単著
掲載誌名	SSRN
掲載区分	国外
出版社・発行元	ELSEVIER
担当区分	筆頭著者,最終著者
概要	This paper develops a minimal international-trade extension of a standard model of com- petition between vertically differentiated platforms in a two-sided market. Building on Zennyo (2016), we preserve the sequential structure of the game (royalties first, device prices second) and the developer entry mechanism. We introduce a per-unit tariffon the imported (high-quality) device and derive a closed-form subgame-perfect equilibrium. We find that, despite asymmetric qualities and a trade-policy wedge, equilibrium royalties remain symmetric and perfectly tariff- invariant. The tariffshifts both consumer demand and software variety toward the domestic (low-quality) platform. Furthermore, we provide explicit optimal-tariff　formulas under both strategic-trade and full domestic welfare objectives.