Hostname: page-component-cd9895bd7-gxg78 Total loading time: 0 Render date: 2024-12-27T13:30:05.988Z Has data issue: false hasContentIssue false

A Note on Subadditivity of Zero-Utility Premiums

Published online by Cambridge University Press:  09 August 2013

Michel M. Denuit
Affiliation:
Institut de statistique, biostatistique et sciences actuarielles (ISBA), Université Catholique de Louvain, B-1348 Louvain-la-Neuve, Belgium
Louis Eeckhoudt
Affiliation:
IESEG School of Management, LEM, Lille, FranceandCORE, Université Catholique de Louvain, Louvain-la-Neuve, Belgium
Mario Menegatti
Affiliation:
Dipartimento di Economia, Università degli Studi di Parma, Parma, Italy

Abstract

Many papers in the literature have adopted the expected utility paradigm to analyze insurance decisions. Insurance companies manage policies by growing, by adding independent risks. Even if adding risks generally ultimately decreases the probability of insolvency, the impact on the insurer's expected utility is less clear. Indeed, it is not true that the risk aversion toward the additional loss generated by a new policy included in an insurance portfolio always decreases with the number of contracts already underwritten. The present paper derives conditions under which zero-utility premium principles are subadditive for independent risks. It is shown that subadditivity is the exception rather than the rule: the zero-utility premium principle generates a superadditive risk premium for most common utility functions. For instance, all completely monotonic utility functions generate superadditive zero-utility premiums. The main message of the present paper is thus that the zero-utility premium for a marginal policy is generally not sufficient to guarantee the formation of insurance portfolios without additional capital.

Type
Research Article
Copyright
Copyright © International Actuarial Association 2011

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Borch, K. (1962) Equilibrium in a reinsurance market. Econometrica 3, 424444.CrossRefGoogle Scholar
Brockett, P.L. (1983) On the misuse of the central limit theorem in some risk calculations. Journal of Risk and Insurance 50, 727731.Google Scholar
Bühlmann, H. (1970) Mathematical Methods in Risk Theory. Springer Verlag, New York.Google Scholar
Bühlmann, H. (1985) Premium calculation from top down. Astin Bulletin 15, 89101.Google Scholar
Diamond, D.W. (1984) Financial intermediation and delegated monitoring. Review of Economic Studies 51, 393414.Google Scholar
Eeckhoudt, L. and Gollier, C. (2001) Which shape for the curve of risk? Journal of Risk and Insurance 68, 387402.CrossRefGoogle Scholar
Gerber, H.U. and Goovaerts, M.J. (1981) On the representation of additive principles of premium calculation. Scandinavian Actuarial Journal, 221227.Google Scholar
Goovaerts, M.J., De Vijlder, F. and Haezendonck, J. (1984) Insurance Premiums. North-Holland, Amsterdam.Google Scholar
Goovaerts, M.J., Kaas, R., Laeven, R.J.A. and Tang, Q. (2004) A comonotonic image of independence for additive risk measures. Insurance: Mathematics and Economics 35, 581594.Google Scholar
Goovaerts, M.J., Kaas, R. and Laeven, R.J.A. (2010) A note on additive risk measures in rank-dependent utility. Insurance: Mathematics and Economics 47, 187189.Google Scholar
Hammarlid, O. (2005) When to accept a sequence of gambles. Journal of Mathematical Economics 41, 974982.Google Scholar
Hellwig, M.F. (1995) The assessment of large compounds of independent gambles. Journal of Economic Theory 67, 299326.Google Scholar
Kaas, R., Goovaerts, M.J., Dhaene, J. and Denuit, M. (2008) Modern Actuarial Risk Theory Using R. Springer, New York.Google Scholar
Kimball, M.S. (1993) Standard risk aversion. Econometrica 61, 589611.CrossRefGoogle Scholar
Lippman, S.A. and Mamer, J.W. (1988) When many wrongs make a right. Probability in the Engineering and Informational Sciences 2, 115127.Google Scholar
Maggi, M., Magnani, U. and Menegatti, M. (2006) On the relationship between absolute prudence and absolute risk aversion. Decisions in Economics and Finance 29, 155160.Google Scholar
Menegatti, M. (2001) On the conditions for precautionary saving. Journal of Economic Theory 98, 189193.Google Scholar
Nielsen, L.T. (1985) Attractive compounds of unattractive investments and gambles. Scandinavian Journal of Economics 87, 463473.Google Scholar
Pratt, J.W. (1964) Risk aversion in the small and in the large. Econometrica 32, 122136.CrossRefGoogle Scholar
Pratt, J. and Zeckhauser, R. (1987) Proper risk aversion. Econometrica 55, 143154.Google Scholar
Ross, S.A. (1999) Adding risks: Samuelson's fallacy of large numbers revisited. Journal of Financial and Quantitative Analysis 34, 323339.Google Scholar
Samuelson, P.A. (1963) Risk and uncertainty: A fallacy of large numbers. Scientia 98, 108113.Google Scholar
Smith, M.L. and Kane, S.A. (1994) The law of large numbers and the strength of insurance. In “Insurance, Risk Management, and Public Policy” edited by Gustavson, S.A. and Harrington, S.E., Kluwer Academic Publishers, pp. 127.Google Scholar
Thomson, R.J. (2005) The pricing of liabilities in an incomplete market using dynamic mean-variance hedging. Insurance: Mathematics and Economics 36, 441–55.Google Scholar
Van Heerwaarden, A.E., Kaas, R. and Goovaerts, M.J. (1989) Properties of the Esscher premium calculation principle. Insurance: Mathematics and Economics 8, 261267.Google Scholar