Hampus Engsner: Dynamic valuation of insurance cash flows subject to capital requirements
Time: Fri 2021-05-28 13.00
Location: Zoom, email organiser
Doctoral student: Hampus Engsner
Opponent: Patrick Cheridito (ETH Zurich)
Supervisor: Filip Lindskog
Insurance companies are required by regulation to be in possession of liquid assets that ensure that they can meet their obligations to policyholders with high probability. The amount is usually determined by an actuarial valuation, with for instance the Solvency II regulatory framework providing standard formulae. In this thesis we investigate a valuation procedure where the value of the liability cash flow is determined via a backwards recursive relationship, meaning that the value at time t depends on the value at time t+1. The value corresponds to an amount required to be able to raise capital from an external capital provider with limited liability, in order to meet capital requirements imposed by a regulating body.
Paper I describes the valuation philosophy that will more or less be shared by all papers in the thesis. It establishes a recursive relationship given via a mapping, that satisfy the properties of a dynamic monetary utility function. Conditions are given where finite p:th moments are preserved in the recursion and a link to the well known subject of dynamic monetary risk measures and utility functions is established. The structure of the recursion is used to find closed-form values for certain stochastic processes, most importantly in the case where we have jointly Gaussian cash flows.
Paper II explores the valuation procedure in the presence of a risk-neutral probability measure Q, which correctly prices the financial instruments that are priced by the financial market but is also assumed to express the risk aversion toward non-hedgeable insurance risk of the capital provider. We show that the valuation procedure is equivalent to an optimal stopping problem, giving us an alternative way to define the valuation procedure. We reproduce many of the structural results from Paper I under the assumed conditions. We also consider the choice of replicating portfolio under different criteria, especially the criterion of minimizing the need for external capital.
Paper III considers the discrete-time valuation from paper I, but where the valuation times form an arbitrary partition of the time interval on which the runoff of the liability occurs. We investigate the properties of the value as the mesh of the partition goes to zero. We define a "continuous-time value" of a liability cash flow and find closed form expressions and some structural results for classes of stochastic processes including Lévy processes and Itô diffusions.
Paper IV tackles the numerical difficulties of performing the recursive valuation procedure where a closed-form value cannot be found. Under Markovian assumptions, a so-called least-squares Monte Carlo (LSM) algorithm is investigated, a method that was developed to tackle optimal stopping problems. We show some overarching consistency results for the LSM algorithm in the general setting of dynamic monetary utility functions and also explore numeric performance for some example models.
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