Understanding how climate factors influence mortality is crucial for demographic forecasting, risk management, and public health planning. My research explores the intersection of mortality modeling and climate-related risks through two key projects:

• Granular mortality modeling with temperature and epidemic shocks: a three-state regime-switching approach
  In this project, we develop a regime-switching framework to model deviations in mortality caused by temperature extremes and epidemic shocks. The model features three states: a baseline seasonal trend, an environmental shock state for heatwaves, and a respiratory shock state capturing excess mortality from influenza and COVID-19. By incorporating temperature and epidemic incidence data, we provide dynamic forecasts that help assess climate-driven mortality risks across regions and age groups.
  
  Collaborators: Jens Robben and Torsten Kleinow

• Mortality and the Actuaries Climate Index (ACI)
  This project investigates the association between mortality rates and climate variables captured by the Actuaries Climate Index (ACI). We examine how different components of the ACI—such as temperature extremes, heavy precipitation, and drought conditions—correlate with historical mortality trends. Our goal is to develop models that link climate variability to long-term mortality risks, providing insights into how climate change may shape future longevity trends.
  
  Collaborators: Kenneth Zhou and Melanie Patten

Our current research project challenges the conventional assumption that investment strategies for participating life insurance are exogenous. We delve into the dynamic nature of asset management by considering how insurers might adjust their investment tactics in response to fluctuations in liability values and asset-liability ratios. Our study sheds light on the impacts of endogenous investment strategies on contract valuations and solvency risks.

Furthermore, we aim to propose a data-driven method that leverages neural networks to identify optimal hedging strategies for these contracts. This innovative approach promises to reveal critical insights into the nuanced differences between exogenous and endogenous liabilities in life insurance. Stay tuned for more on this exciting venture!

Collaborator: Peter Hieber

Standard age-period-cohort mortality models such as the Lee-Carter model do not allow for pandemic jumps. Models with jumps in the literature either assume transitory effects of one year only or permanent effects. In this paper, we propose an extension of the Lee-Carter model with vanishing jumps and using COVID-19 data, we show that such approach outperforms the Liu-Li approach which considers transitory jumps.

Published paper on Bayesian mortality modelling with pandemics: a vanishing jump approach

Collaborators: Julius Goes and Anne Leucht

Selection of an appropriate longevity model and detection of abrupt changes in longevity dynamics is critical for the insurance industry.

In the first part of this project, we investigate the model choice issue by the use of regularization and bayesian statistics.

• In the first paper, we propose to smooth and forecast the mortality surface by the use of regularization. Regularization is a great tool to reduce overfitting and we show that this approach outperforms the P-splines method.

  Published paper on Smoothing and forecasting mortality using regularization and cross-validation

• In the second paper, we propose two Bayesian model averaging techniques based on leave-future-out validation. We show that such approaches tend to outperform the standard BMA in terms of robustness and accuracy.

  Published paper on Bayesian model averaging for mortality forecasting using leave-future-out validation

In the second part of the project, we tackle the change-point detection problem for longevity trends and for multi-sensors (corresponding to monitoring of different age groups or different classes of policyholders). A sudden change in the longevity trend can induce serious financial consequences, and it is necessary to react as soon as data would suggest it. The specific context of COVID-19, and its potential impact on longevity trend will also be covered. Therefore, we will provide optimal surveillance strategies suited for longevity risk.

Collaborators: Nicole El Karoui, Pierre-Olivier Goffard, Stephane Loisel and Yahia Salhi

Pricing life insurance contracts with financial death and survival guarantees boils down to solving a high-dimensional pricing problem. In this project, we show that the price is the solution of a multi-dimensional partial differential equation in continuous time. By using the connection between PDE and BSDE, we solve the problem numerically by deep neural networks.

Published paper on Pricing equity-linked life insurance contracts with multiple risk factors by neural networks

Collaborator: Lukasz Delong

Current approaches to fair valuation in insurance often follow a two-step approach, combining quadratic hedging with application of a risk measure on the residual liability, to obtain a cost-of-capital margin. In such approaches, the preferences represented by the regulatory risk measure are not reflected in the hedging process. We address this issue by an alternative two-step hedging procedure, based on generalised regression arguments, which leads to portfolios that are neutral with respect to a risk measure, such as Value-at-Risk or the expectile. First, a portfolio of traded assets aimed at replicating the liability is determined by local quadratic hedging. Second, the residual liability is hedged using an alternative objective function. The risk margin is then defined as the cost of the capital required to hedge the residual liability. In the case quantile regression is used in the second step, yearly solvency constraints are naturally satisfied; furthermore, the portfolio is a risk minimiser among all hedging portfolios that satisfy such constraints. We present a neural network algorithm for the valuation and hedging of insurance liabilities based on a backward iterations scheme. The algorithm is fairly general and easily applicable, as it only requires simulated paths of risk drivers.

Published paper on Insurance valuation: a two-step generalized regression approach

Collaborators: Valeria Bignozzi and Andreas Tsanakas