Acta mathematica scientia,Series A ›› 2016, Vol. 36 ›› Issue (2): 362-379.

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Optimal Portfolio Problems for an Insurance Company Under Default Risk and Model Uncertainty

Zheng Xiaoxiao1, Sun Zhongyang1, Zhang Xin2   

  1. 1 School of Mathematical Sciences, Nankai University, Tianjin 300071;
    2 Department of Mathematics, Southeast University, Nanjing 210096
  • Received:2015-09-19 Revised:2016-01-11 Online:2016-04-25 Published:2016-04-25
  • Supported by:

    Supported by the NSFC (11371020)

Abstract:

In this paper, we investigate a stochastic portfolio optimization problem with model uncertainty and default risk. We assume that an insurer can invest his money into financial market where a savings account, a stock and a corporate bond are available, and aim to maximize the CARA utility of the terminal wealth. Furthermore, to take the model uncertainty into consideration, we formulate the optimization problem as a zero-sum stochastic differential game problem between market and the insurer. By using dynamic programming principle, we derive the Hamilton-Jacobi-Bellman-Isaacs (HJBI) equation, and then find the optimal policy under the "worst-case" scenario for both jump-diffusion model and its diffusion approximation.

Key words: Stochastic differential game, HJBI equation, Defaultable bond, Model uncertainty, CARA utility maximization

CLC Number: 

  • O211.6
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