財政・公共経済ワークショップ
Public Economics Workshop

2013年5月23日（木）18:00-20:00

東京大学大学院経済学研究科 学術交流棟 （小島ホール）
１階第２セミナー室 [MAP]

佐藤主光 (一橋大学)

Optimal Income Taxation and Risk: The Extensive-Margin Case (joint with Robin Boadway) [PDF]

The optimal income tax structure is studied in a setting in which workers make discrete labor market decisions and earnings are uncertain. Workers differ continuously along a single dimension that reflects their skills as well as their disutility of work in different jobs. A discrete number of skill-types of jobs are available in perfectly elastic supply. Each job yields a stochastic distribution of wages, where the distribution differs among skill-types. The amount of work in each job is fixed, so there is no intensive labor-supply decision and wages reflect earnings. Expected wages for a given skill-type of job are higher for higher-skilled workers. Workers first choose a job based on the distribution of wages they expect to earn in different jobs. Once jobs are chosen, wages are revealed and workers decide whether to participate in the job or to become voluntarily unemployed. Each job will be associated with a distribution of wages, and the same wage will be paid by more than one type of job. Under reasonable conditions, workers segment themselves by skill levels into jobs. We analyze the optimal income tax structure given these two margins of decision-making, job choice and participation. The optimal tax will reflect insurance (since earnings are uncertain when jobs are chosen), redistribution (since persons of higher skills earn more), and efficiency (since taxes affect both job choice and participation). The form of the tax structure is comparable to that obtained when labor supply can be varied along the intensive margin.

Key Words: optimal income taxation, risk, extensive margin JEL Classification: H21, H24

2014年1月31日（金）16:40-18:20

東京大学大学院経済学研究科 学術交流棟 （小島ホール）
2階　第3セミナー室 [MAP]

松岡佑和 (東京大学博士課程)

市町村合併が老人福祉費に与えた影響

2014年3月18日（火）1) 15:30-16:40, 2) 16:40-18:20

東京大学大学院経済学研究科 学術交流棟 （小島ホール）
2階　第3セミナー室 [MAP]

1) 15:30-16:40 小西秀樹（早稲田大学）

Financing Social Security by Consumption Tax: a Political Economy Perspective

In some developed nations, e.g. Japan, France, Denmark, and Germany, consumption tax is increasingly becoming a popular way to fund social security expenditures, while wage-based taxes have been traditionally used. The paper analyzes how these taxes are combined for social security financing in a political arena of overlapping generations, placing a focus on their effects on inter- and intra-generational redistribution, and examines how population aging affects the political equilibrium. Employing the concept of structure-induced equilibrium invented by Shepsle (1979), the paper shows that a society with slow population growth is likely to have multiple equilibria with social security financed respectively by only wage tax, only consumption tax, and both, while a society with rapid population growth has a unique equilibrium with social security financed by only wage tax.

2) 16:40-18:20 Wolfgang Eggert (University of Freiburg)

Tax Rate Harmonization, Renegotiation and Asymmetric Tax Competition for Prots with Repeated Interaction(joint with Jun-ichi Itaya) [PDF]

This paper analyzes a model of corporate tax competition with repeated interaction and with strategic use of prot shifting within multinationals. We show that international tax coordination is more likely to prevail if the degree of asymmetry in terms of productivity differences between countries is smaller, or if concealment costs of prot shifting are larger when the tax authorities adopt grim-trigger strategies. Allowing for renegotiation in the tax harmonization process generally requires more patient tax authorities to support tax harmonization as a subgame perfect equilibrium. We nd somewhat paradoxical situations where higher costs of prot shifting may make international tax arrangements less sustainable under weakly-renegotiation-proof strategies.