消費外部性、自我保險與最適租稅政策

Consumption Externality, Self-Insurance, and Optimal Taxation

顏志達(Chih-Ta Yen)；翁堃嵐(K. L. Glen Ueng)

消費外部性 ； 自我保險 ； 最適租稅 ； Consumption Externality ； Self-Insurance ； Optimal Taxation

經濟研究

52卷2期（2016 / 07 / 31）

253 - 279

繁體中文

本文建構了一個包含消費外部性的個人自我保險模型，文中有二項主要的發現。第一，當個人偏好為妒忌 (jealousy) 且為風險趨避時，個人均衡的自我保險投入會低於社會的最適水準，此一結果明顯異於Dupor and Liu (2003) 的論點。第二， 當個人均衡屬於低度（過度）自我保險時，假若政府資金的邊際成本 (marginal cost of public funds, MCPF) 等於1，則政府可透過對個人的損失課稅（扣除），或者對其自我保險投入補貼（課稅）來矯正此一扭曲。然而，當政府資金的邊際成本大於1 時，假若個人均衡屬於低度自我保險時，則政府應對個人的損失課稅；反之，當個人均衡屬於過度自我保險時，則應對個人從事自我保險的投入課稅。

This paper constructs a self-insurance model in the presence of consumption externality. We have two major findings. First, if an individual is jealous and risk averse, then the equilibrium level of self-insurance will be lower than the social optimum. This result is significantly different from that of Dupor and Liu (2003). Second, when the marginal cost of public funds (MCPF) equals one, the government should tax (subsidize) losses or subsidize (tax) self-insurance if consumers are under- (over-) insured. However, when the MCPF is greater than one, the government should tax losses if consumers are under-insured and tax self-insurance if consumers are over-insured.

1. 吳朝欽、翁堃嵐(2007)。論所得稅損失扣除政策之福利效果。經濟論文，35(2)，115-148。
   連結：
2. Abel, A. B.(2005).Optimal Taxation When Consumers Have Endogenous Benchmark Levels of Consumption.The Review of Economic Studies,72(1),21-42.
3. Boadway, R.,Leite-Monteiro, M.,Marchand, M.,Pestieau, P.(2006).Social Insurance and Redistribution with Moral Hazard and Adverse Selection.The Scandinavian Journal of Economics,108(2),279-298.
4. Boskin, M. J.,Sheshinski, E.(1978).Optimal Redistributive Taxation When Individual Welfare Depends upon Relative Income.The Quarterly Journal of Economics,92(4),589-601.
5. Brown, J. R.(2003).Redistribution and Insurance: Mandatory Annuitization with Mortality Heterogeneity.The Journal of Risk and Insurance,70(1),17-41.
6. Browning, E. K.(1976).The Marginal Cost of Public Funds.Journal of Political Economy,84(2),283-298.
7. Corneo, G.,Jeanne, O.(2001).Status, the Distribution of Wealth, and Growth.The Scandinavian Journal of Economics,103(2),283-293.
8. Cremer, H.,Pestieau, P.(1996).Redistributive Taxation and Social Insurance.International Tax and Public Finance,3(3),281-295.
9. Diamond, P.(1992).Organizing the Health Insurance Market.Econometrica,60(6),1233-1254.
10. Dupor, B.,Liu, W. F.(2003).Jealousy and Equilibrium Overconsumption.The American Economic Review,93(1),423-428.
11. Ehrlich, I.,Becker, G. S.(1972).Market Insurance, Self-Insurance,and Self-Protection.Journal of Political Economy,80(4),623-648.
12. Feldstein, M.(1997).How Big Should Government Be?.National Tax Journal,50(2),197-213.
13. Howarth, R. B.(2006).Optimal Environmental Taxes under Relative Consumption Effects.Ecological Economics,58(1),209-219.
14. Huang, R. J.,Tzeng, L. Y.(2008).Consumption Externality and Equilibrium Underinsurance.The Journal of Risk and Insurance,75(4),1039-1054.
15. Kaplow, L.(1991).Incentives and Government Relief for Risk.Journal of Risk and Uncertainty,4(2),167-175.
16. Kaplow, L.(1992).Income Tax Deductions for Losses as Insurance.The American Economic Review,82(4),1013-1017.
17. Lee, K.(2005).Wealth Effects on Self-Insurance and Self-Protection against Monetary and Nonmonetary Losses.The Geneva Risk and Insurance Review,30(2),147-159.
18. Ljungqvist, L.,Uhlig, H.(2000).Tax Policy and Aggregate Demand Management under Catching up with the Joneses.The American Economic Review,90(3),356-366.
19. Mitchell, O. S.(1996).NBER Working PaperNBER Working Paper,未出版
20. Neary, J. P.(1994).Cost Asymmetries in International Subsidy Games: Should Governments Help Winners or Losers?.Journal of International Economics,37(3-4),197-218.
21. Netzer, N.,Scheuer, F.(2007).Taxation, Insurance, and Precautionary Labor.Journal of Public Economics,91(7-8),1519-1531.
22. Ng, Y. K.(1987).Relative-Income Effects and the Appropriate Level of Public Expenditure.Oxford Economic Papers,39(2),293-300.
23. Persson, M.(1995).Why Are Taxes So High in Egalitarian Societies?.The Scandinavian Journal of Economics,97(4),569-580.
24. Porat, M. M.,Spiegel, U.,Yaari, U.,Zion, U. B.(1991).Market Insurance versus Self Insurance: The Tax-Differential Treatment and Its Social Cost.The Journal of Risk and Insurance,58(4),657-669.