Hostname: page-component-cd9895bd7-8ctnn Total loading time: 0 Render date: 2024-12-23T15:28:39.805Z Has data issue: false hasContentIssue false

SIZE-BIASED TRANSFORM AND CONDITIONAL MEAN RISK SHARING, WITH APPLICATION TO P2P INSURANCE AND TONTINES

Published online by Cambridge University Press:  17 July 2019

Michel Denuit*
Affiliation:
Institut de Statistique, Biostatistique et Sciences Actuarielles - ISBA UCLouvain B-1348 Louvain-la-Neuve, Belgium E-mail: [email protected]

Abstract

Using risk-reducing properties of conditional expectations with respect to convex order, Denuit and Dhaene [Denuit, M. and Dhaene, J. (2012). Insurance: Mathematics and Economics 51, 265–270] proposed the conditional mean risk sharing rule to allocate the total risk among participants to an insurance pool. This paper relates the conditional mean risk sharing rule to the size-biased transform when pooled risks are independent. A representation formula is first derived for the conditional expectation of an individual risk given the aggregate loss. This formula is then exploited to obtain explicit expressions for the contributions to the pool when losses are modeled by compound Poisson sums, compound Negative Binomial sums, and compound Binomial sums, to which Panjer recursion applies. Simple formulas are obtained when claim severities are homogeneous. A couple of applications are considered: first, to a peer-to-peer insurance scheme where participants share the first layer of their respective risks while the higher layer is ceded to a (re)insurer; second, to survivor credits to be shared among surviving participants in tontine schemes.

Type
Research Article
Copyright
© Astin Bulletin 2019 

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

Arratia, R., Goldstein, L., and Kochman, F. (2019) Size bias for one and all. Probability Surveys, 16, 161.CrossRefGoogle Scholar
Brown, M. (2006) Exploiting the waiting time paradox: Applications of the size-biasing transformation. Probability in the Engineering and Informational Sciences 20, 195230.CrossRefGoogle Scholar
Chen, A., Hieber, P., and Klein, J.K. (2019) Tonuity: A novel individual-oriented retirement plan. ASTIN Bulletin 49, 530.CrossRefGoogle Scholar
Denuit, M. (2018) Size-biased risk measures of compound sums. Research report submitted for publication, Available at https://dial.uclouvain.be/pr/boreal/object/boreal:215114Google Scholar
Denuit, M. and Dhaene, J. (2012) Convex order and comonotonic conditional mean risk sharing. Insurance: Mathematics and Economics 51, 265270.Google Scholar
Denuit, M., Dhaene, J., Goovaerts, M.J., and Kaas, R. (2005) Actuarial Theory for Dependent Risks: Measures, Orders and Models. New York: Wiley.CrossRefGoogle Scholar
De Pril, N. (1989) The aggregate claims distribution in the individual model with arbitrary positive claims. ASTIN Bulletin 19, 924.CrossRefGoogle Scholar
Dhaene, J. and Vandebroek, M. (1995) Recursions for the individual model. Insurance: Mathematics and Economics 16, 3138.Google Scholar
Donnelly, C. (2015) Actuarial fairness and solidarity in pooled annuity funds. ASTIN Bulletin 45, 4974.CrossRefGoogle Scholar
Donnelly, C., Guillen, M. and Nielsen, J.P. (2014) Bringing cost transparency to the life annuity market. Insurance: Mathematics and Economics 56, 1427.Google Scholar
Donnelly, C. and Young, J. (2017) Product options for enhanced retirement income. British Actuarial Journal 22, 636656.CrossRefGoogle Scholar
Dutang, CH., Goulet, V. and Pigeon, M. (2008) actuar: An R package for actuarial science. Journal of Statistical Software 25, 137.Google Scholar
Furman, E., Kuznetsov, A. and Zitikis, R. (2018) Weighted risk capital allocations in the presence of systematic risk. Insurance: Mathematics and Economics 79, 7581.Google Scholar
Furman, E. and Landsman, Z. (2005) Risk capital decomposition for a multivariate dependent gamma portfolio. Insurance: Mathematics and Economics 37, 635649.Google Scholar
Furman, E. and Landsman, Z. (2008) Economic capital allocations for non-negative portfolios of dependent risks. ASTIN Bulletin 38, 601619.CrossRefGoogle Scholar
Furman, E. and Zitikis, R. (2008a) Weighted risk capital allocations. Insurance: Mathematics and Economics 43, 263269.Google Scholar
Furman, E. and Zitikis, R. (2008b) Weighted premium calculation principles. Insurance: Mathematics and Economics 42, 459465.Google Scholar
Pakes, A. G. Sapatinas, T. and Fosam, E. B. (1996) Characterizations, length-biasing, and infinite divisibility. Statistical Papers 37, 5369.CrossRefGoogle Scholar
Patil, G.P. and Rao, C.R. (1978) Weighted distributions and size-biased sampling with applications to wildlife populations and human families. Biometrics 34, 179189.CrossRefGoogle Scholar
Sabin, M. J. (2010) Fair Tontine Annuity. Available at https://ssrn.com/abstract=1579932CrossRefGoogle Scholar
Saumard, A. and Wellner, J. A. (2018) Efron’s monotonicity property for measures on R2. Journal of Multivariate Analysis 166, 212224.CrossRefGoogle Scholar
Shaked, M. and Shanthikumar, J. G. (2007) Stochastic Orders. New York: Springer.CrossRefGoogle Scholar
Sundt, B. and Vernic, R. (2009) Recursions for Convolutions and Compound Distributions with Insurance Applications. Berlin: Springer-Verlag.Google Scholar