Equilibrium reinsurance-investment strategy for mean-variance insurers under state dependent risk aversion

In this work, we study the equilibrium reinsurance/ new business and investment strategy for mean-variance insurers, under the assumption that the risk aversion is a function of current wealth level. The surplus of the agents is represented by a sum of a compound process and a linear premium perturbed with a Brownian component. The financial market consists of one riskless asset and a multiple risky assets whose price processes are driven by Poisson random measures and independent Brownian motions. We characterize explicit expressions for the time-consistent Nash equilibrium strategy and the equilibrium value function via a forward-backward stochastic system and an equilibrium condition. An interesting feature of these FBSDEs is that a time parameter is involved, so that they form a flow of FBSDEs. Furthermore, a feedback representation of an equilibrium solution is derived. This solution provides a tool for comparing the equilibrium strategy with those derived in other papers, where some special cases were studied by the dynamic programming argument.