claudia ceci - Academia.edu (original) (raw)

Papers by claudia ceci

Research paper thumbnail of Optimal proportional reinsurance and investment for stochastic factor models

arXiv (Cornell University), Jun 4, 2018

In this work we investigate the optimal proportional reinsurance-investment strategy of an insura... more In this work we investigate the optimal proportional reinsurance-investment strategy of an insurance company which wishes to maximize the expected exponential utility of its terminal wealth in a finite time horizon. Our goal is to extend the classical Cramér-Lundberg model introducing a stochastic factor which affects the intensity of the claims arrival process, described by a Cox process, as well as the insurance and reinsurance premia. Using the classical stochastic control approach based on the Hamilton-Jacobi-Bellman equation we characterize the optimal strategy and provide a verification result for the value function via classical solutions of two backward partial differential equations. Existence and uniqueness of these solutions are discussed. Results under various premium calculation principles are illustrated and a new premium calculation rule is proposed in order to get more realistic strategies and to better fit our stochastic factor model. Finally, numerical simulations are performed to obtain sensitivity analyses.

Research paper thumbnail of Optimal reinsurance via BSDEs in a partially observable model with jump clusters

Finance and Stochastics

We investigate an optimal reinsurance problem when the loss process exhibits jump clustering feat... more We investigate an optimal reinsurance problem when the loss process exhibits jump clustering features and the insurance company has restricted information about the loss process. We maximise expected exponential utility of terminal wealth and show that an optimal strategy exists. By exploiting both the Kushner–Stratonovich and Zakai approaches, we provide the equation governing the dynamics of the (infinite-dimensional) filter and characterise the solution of the stochastic optimisation problem in terms of a BSDE, for which we prove existence and uniqueness of a solution. After discussing the optimal strategy for a general reinsurance premium, we provide more explicit results in some relevant cases.

Research paper thumbnail of Optimal proportional reinsurance and investment for stochastic factor models

arXiv (Cornell University), Jun 4, 2018

In this work we investigate the optimal proportional reinsurance-investment strategy of an insura... more In this work we investigate the optimal proportional reinsurance-investment strategy of an insurance company which wishes to maximize the expected exponential utility of its terminal wealth in a finite time horizon. Our goal is to extend the classical Cramér-Lundberg model introducing a stochastic factor which affects the intensity of the claims arrival process, described by a Cox process, as well as the insurance and reinsurance premia. Using the classical stochastic control approach based on the Hamilton-Jacobi-Bellman equation we characterize the optimal strategy and provide a verification result for the value function via classical solutions of two backward partial differential equations. Existence and uniqueness of these solutions are discussed. Results under various premium calculation principles are illustrated and a new premium calculation rule is proposed in order to get more realistic strategies and to better fit our stochastic factor model. Finally, numerical simulations are performed to obtain sensitivity analyses.

Research paper thumbnail of Local risk-minimization under restricted information to asset prices

arXiv (Cornell University), Dec 16, 2013

In this paper we investigate the local risk-minimization approach for a semimartingale financial ... more In this paper we investigate the local risk-minimization approach for a semimartingale financial market where there are restrictions on the available information to agents who can observe at least the asset prices. We characterize the optimal strategy in terms of suitable decompositions of a given contingent claim, with respect to a filtration representing the information level, even in presence of jumps. Finally, we discuss some practical examples in a Markovian framework and show that the computation of the optimal strategy leads to filtering problems under the real-world probability measure and under the minimal martingale measure.

Research paper thumbnail of Modelling the Industrial Production of Electric and Gas Utilities through the CIR3 Model

Social Science Research Network, 2023

Research paper thumbnail of Indifference pricing of life insurance contracts via BSDEs under partial information

arXiv (Cornell University), Mar 31, 2018

In this paper we investigate the pricing problem of a pure endowment contract when the insurance ... more In this paper we investigate the pricing problem of a pure endowment contract when the insurance company has a limited information on the mortality intensity of the policyholder. The payoff of this kind of policies depends on the residual life time of the insured as well as the trend of a portfolio traded in the financial market, where investments in a riskless asset, a risky asset and a longevity bond are allowed. We propose a modeling framework that takes into account mutual dependence between the financial and the insurance markets via an observable stochastic process, which affects the risky asset and the mortality index dynamics. Since the market is incomplete due to the presence of basis risk, in alternative to arbitrage pricing we use expected utility maximization under exponential preferences as evaluation approach, which leads to the so-called indifference price. Under partial information this methodology requires filtering techniques that can reduce the original control problem to an equivalent problem in complete information. Using stochastic dynamics techniques, we characterize the indifference price of the insurance derivative in terms of the solutions of two backward stochastic differential equations. Finally, we discuss two special cases where we get a more explicit representation of the indifference price process.

Research paper thumbnail of On the hedging strategies for defaultable claims under incomplete information

arXiv (Cornell University), Aug 25, 2016

In this paper we investigate the hedging problem of a defaultable claim with recovery at default ... more In this paper we investigate the hedging problem of a defaultable claim with recovery at default time via the local risk-minimization approach when investors have a restricted information on the market. We assume that the stock price process dynamics depends on an exogenous unobservable stochastic factor and that at any time, investors may observe the risky asset price and know if default has occurred or not. We characterize the optimal strategy in terms of the integrand in the Galtchouk-Kunita-Watanabe decomposition of the defaultable claim with respect to the minimal martingale measure and the available information flow. Finally, we provide an explicit formula by means of predictable projection of the corresponding hedging strategy under full information with respect to the natural filtration of the risky asset price and the minimal martingale measure in a Markovian setting via filtering.

Research paper thumbnail of The Zakai equation of nonlinear filtering for jump-diffusion observation: existence and uniqueness

arXiv (Cornell University), Oct 16, 2012

This paper is concerned with the nonlinear filtering problem for a general Markovian partially ob... more This paper is concerned with the nonlinear filtering problem for a general Markovian partially observed system (X, Y), whose dynamics is modeled by correlated jump-diffusions having common jump times. At any time t ∈ [0, T ], the σ-algebra F Y t := σ{Y s : s ≤ t} provides all the available information about the signal X t. The central goal of stochastic filtering is to characterize the filter, π t , which is the conditional distribution of X t , given the observed data F Y t. It has been proved in [7] that π is the unique probability measure-valued process satisfying a nonlinear stochastic equation, the so-called Kushner-Stratonovich equation (KS-equation). In this paper the aim is to describe the filter π in terms of the unnormalized filter ̺, which is solution to a linear stochastic differential equation, the so-called Zakai equation. We prove equivalence between strong uniqueness for the solution to the Kushner Stratonovich equation and strong uniqueness for the solution to the Zakai one and, as a consequence, we deduce pathwise uniqueness for the solutions to the Zakai equation by applying the Filtered Martingale Problem approach ([25, 7]). To conclude, some particular cases are discussed.

Research paper thumbnail of Optimal reinsurance via BSDEs in a partially observable model with jump clusters

arXiv (Cornell University), Jul 12, 2022

We investigate the optimal reinsurance problem when the loss process exhibits jump clustering fea... more We investigate the optimal reinsurance problem when the loss process exhibits jump clustering features and the insurance company has restricted information about the loss process. We maximize expected exponential utility of terminal wealth and show that an optimal solution exists. By exploiting both the Kushner-Stratonovich and Zakai approaches, we provide the equation governing the dynamics of the (infinite-dimensional) filter and characterize the solution of the stochastic optimization problem in terms of a BSDE, for which we prove existence and uniqueness of solution. After discussing the optimal strategy for a general reinsurance premium, we provide more explicit results in some relevant cases.

Research paper thumbnail of Modelling the industrial production of electric and gas utilities through a stochastic three-factor model

Research paper thumbnail of Discipline: Mathématiques

pour le grade de DOCTEUR de per il titolo di DOTTORE DI RICERCA l’Université de Paris 13 dell ’ U... more pour le grade de DOCTEUR de per il titolo di DOTTORE DI RICERCA l’Université de Paris 13 dell ’ Università LUISS GUIDO CARLI

Research paper thumbnail of Une propriété forte de branchements

Nous exposons le prolongement fort de la propriete de branchements a travers une topologie sur le... more Nous exposons le prolongement fort de la propriete de branchements a travers une topologie sur les arbres

Research paper thumbnail of A Benchmark Approach to Risk-Minimization under Partial Information

In this paper we study a risk-minimizing hedging problem for a semimartingale incomplete financia... more In this paper we study a risk-minimizing hedging problem for a semimartingale incomplete financial market where d+1 assets are traded continuously and whose price is expressed in units of the numéraire portfolio. According to the so-called benchmark approach, we investigate the (benchmarked) risk-minimizing strategy in the case where there are restrictions on the available information. More precisely, we characterize the optimal strategy as the integrand appearing in the Galtchouk-Kunita-Watanabe decomposition of the benchmarked claim under partial information and provide its description in terms of the integrands in the classical Galtchouk-Kunita-Watanabe decomposition under full information via dual predictable projections. Finally, we apply the results in the case of a Markovian jump-diffusion driven market model where the assets prices dynamics depend on a stochastic factor which is not observable by investors.

Research paper thumbnail of Risk-Minimizing Hedging of Counterparty Risk

We study dynamic hedging of counterparty risk for a portfolio of credit derivatives. Our empirica... more We study dynamic hedging of counterparty risk for a portfolio of credit derivatives. Our empirically driven credit model consists of interacting default intensities which ramp up and then decay after the occurrence of credit events. Using the Galtchouk-Kunita-Watanabe decomposition of the counterparty risk price payment stream, we recover a closed-form representation for the risk minimizing strategy in terms of classical solutions to nonlinear recursive systems of Cauchy problems. We discuss applications of our framework to the most prominent class of credit derivatives, including credit swap and risky bond portfolios, as well as first-to-default claims.

Research paper thumbnail of Optimal Reduction of Public Debt under Partial Observation of the Economic Growth

We consider a government that aims at reducing the debt-to-gross domestic product (GDP) ratio of ... more We consider a government that aims at reducing the debt-to-gross domestic product (GDP) ratio of a country. The government observes the level of the debt-to-GDP ratio and an indicator of the state of the economy, but does not directly observe the development of the underlying macroeconomic conditions. The government's criterion is to minimize the sum of the total expected costs of holding debt and of debt's reduction policies. We model this problem as a singular stochastic control problem under partial observation. The contribution of the paper is twofold. Firstly, we provide a general formulation of the model in which the level of debt-to-GDP ratio and the value of the macroeconomic indicator evolve as a diffusion and a jump-diffusion, respectively, with coefficients depending on the regimes of the economy. These are described through a finite-state continuous-time Markov chain. We reduce via filtering techniques the original problem to an equivalent one with full informati...

Research paper thumbnail of The Föllmer-Schweizer decomposition under incomplete information

In this paper we study the Föllmer-Schweizer decomposition of a square integrable random variable... more In this paper we study the Föllmer-Schweizer decomposition of a square integrable random variable ξ with respect to a given semimartingale S under restricted information. Thanks to the relationship between this decomposition and that of the projection of ξ with respect to the given information flow, we characterize the integrand appearing in the Föllmer-Schweizer decomposition under partial information in the general case where ξ is not necessarily adapted to the available information level. For partially observable Markovian models where the dynamics of S depends on an unobservable stochastic factor X, we show how to compute the decomposition by means of filtering problems involving functions defined on an infinite-dimensional space. Moreover, in the case of a partially observed jump-diffusion model where X is described by a pure jump process taking values in a finite dimensional space, we compute explicitly the integrand in the Föllmer-Schweizer decomposition by working with finit...

Research paper thumbnail of Value adjustments and dynamic hedging of reinsurance counterparty risk

Reinsurance counterparty credit risk (RCCR) is the risk of a loss arising from the fact that a re... more Reinsurance counterparty credit risk (RCCR) is the risk of a loss arising from the fact that a reinsurance company is unable to fulfill her contractual obligations towards the ceding insurer. RCCR is an important risk category for insurance companies which, so far, has been addressed mostly via qualitative approaches. In this paper we therefore study value adjustments and dynamic hedging for RCCR. We propose a novel model that accounts for contagion effects between the default of the reinsurer and the price of the reinsurance contract. We characterize the value adjustment in a reinsurance contract via a partial integro-differential equation (PIDE) and derive the hedging strategies using a quadratic method. The paper closes with a simulation study which shows that dynamic hedging strategies have the potential to significantly reduce RCCR.

Research paper thumbnail of Li ce nse d unde r the Cre at ive Commons Att ri but ion Noncomme rci al N o De rivati ves RISK MINIMIZING HEDGING IN A PARTIALLY OBSERVED HIGH FREQUENCY DATA MODEL: A FILTERING APPROACH

Risk-minimizing hedging strategies for contingent claims are studied in a general model for intra... more Risk-minimizing hedging strategies for contingent claims are studied in a general model for intraday stock price movements in the case of partial information. The dynamics of the risky asset price is described throught a marked point process Y, whose local characteristics depend on some unobservable hidden state variable X, described by a jump-diffusion process. In the model presented the processes Y and X may have common jump times, which means that the trading activity may affect the law of X and could be also related to the presence of catastrophic events. The hedger is restricted to observing past asset prices. Thus we are in presence not only of an incomplete market situation but also of partial information. Assuming that the price of the risky asset is modeled directly under a martingale measure, the computation of the risk-minimizing hedging strategy under this partial information leads to a filtering problem with marked point process observations. The conditional law of X gi...

Research paper thumbnail of Hedging of unit-linked life insurance contracts with unobservable mortality hazard rate via local risk-minimization

In this paper we investigate the local risk-minimization approach for a combined financial-insura... more In this paper we investigate the local risk-minimization approach for a combined financial-insurance model where there are restrictions on the information available to the insurance company. In particular we assume that, at any time, the insurance company may observe the number of deaths from a specific portfolio of insured individuals but not the mortality hazard rate. We consider a financial market driven by a general semimartingale and we aim to hedge unit-linked life insurance contracts via the local risk-minimization approach under partial information. The F\"ollmer-Schweizer decomposition of the insurance claim and explicit formulas for the optimal strategy for pure endowment and term insurance contracts are provided in terms of the projection of the survival process on the information flow. Moreover, in a Markovian framework, we reduce to solve a filtering problem with point process observations.

Research paper thumbnail of 4 Hedging of Unit-Linked Life Insurance Contracts with Unobservable Mortality Hazard Rate via Local Risk-Minimization

In this paper we investigate the local risk-minimization approach for a combined financial-insura... more In this paper we investigate the local risk-minimization approach for a combined financial-insurance model where there are restrictions on the information available to the insurance company. In particular we assume that, at any time, the insurance company may observe the number of deaths from a specific portfolio of insured individuals but not the mortality hazard rate. We consider a financial market driven by a general semimartingale and we aim to hedge unit-linked life insurance contracts via the local risk-minimization approach under partial information. The Föllmer-Schweizer decomposition of the insurance claim and explicit formulas for the optimal strategy for pure endowment and term insurance contracts are provided in terms of the projection of the survival process on the information flow. Moreover, in a Markovian framework, we reduce to solve a filtering problem with point process observations.

Research paper thumbnail of Optimal proportional reinsurance and investment for stochastic factor models

arXiv (Cornell University), Jun 4, 2018

In this work we investigate the optimal proportional reinsurance-investment strategy of an insura... more In this work we investigate the optimal proportional reinsurance-investment strategy of an insurance company which wishes to maximize the expected exponential utility of its terminal wealth in a finite time horizon. Our goal is to extend the classical Cramér-Lundberg model introducing a stochastic factor which affects the intensity of the claims arrival process, described by a Cox process, as well as the insurance and reinsurance premia. Using the classical stochastic control approach based on the Hamilton-Jacobi-Bellman equation we characterize the optimal strategy and provide a verification result for the value function via classical solutions of two backward partial differential equations. Existence and uniqueness of these solutions are discussed. Results under various premium calculation principles are illustrated and a new premium calculation rule is proposed in order to get more realistic strategies and to better fit our stochastic factor model. Finally, numerical simulations are performed to obtain sensitivity analyses.

Research paper thumbnail of Optimal reinsurance via BSDEs in a partially observable model with jump clusters

Finance and Stochastics

We investigate an optimal reinsurance problem when the loss process exhibits jump clustering feat... more We investigate an optimal reinsurance problem when the loss process exhibits jump clustering features and the insurance company has restricted information about the loss process. We maximise expected exponential utility of terminal wealth and show that an optimal strategy exists. By exploiting both the Kushner–Stratonovich and Zakai approaches, we provide the equation governing the dynamics of the (infinite-dimensional) filter and characterise the solution of the stochastic optimisation problem in terms of a BSDE, for which we prove existence and uniqueness of a solution. After discussing the optimal strategy for a general reinsurance premium, we provide more explicit results in some relevant cases.

Research paper thumbnail of Optimal proportional reinsurance and investment for stochastic factor models

arXiv (Cornell University), Jun 4, 2018

In this work we investigate the optimal proportional reinsurance-investment strategy of an insura... more In this work we investigate the optimal proportional reinsurance-investment strategy of an insurance company which wishes to maximize the expected exponential utility of its terminal wealth in a finite time horizon. Our goal is to extend the classical Cramér-Lundberg model introducing a stochastic factor which affects the intensity of the claims arrival process, described by a Cox process, as well as the insurance and reinsurance premia. Using the classical stochastic control approach based on the Hamilton-Jacobi-Bellman equation we characterize the optimal strategy and provide a verification result for the value function via classical solutions of two backward partial differential equations. Existence and uniqueness of these solutions are discussed. Results under various premium calculation principles are illustrated and a new premium calculation rule is proposed in order to get more realistic strategies and to better fit our stochastic factor model. Finally, numerical simulations are performed to obtain sensitivity analyses.

Research paper thumbnail of Local risk-minimization under restricted information to asset prices

arXiv (Cornell University), Dec 16, 2013

In this paper we investigate the local risk-minimization approach for a semimartingale financial ... more In this paper we investigate the local risk-minimization approach for a semimartingale financial market where there are restrictions on the available information to agents who can observe at least the asset prices. We characterize the optimal strategy in terms of suitable decompositions of a given contingent claim, with respect to a filtration representing the information level, even in presence of jumps. Finally, we discuss some practical examples in a Markovian framework and show that the computation of the optimal strategy leads to filtering problems under the real-world probability measure and under the minimal martingale measure.

Research paper thumbnail of Modelling the Industrial Production of Electric and Gas Utilities through the CIR3 Model

Social Science Research Network, 2023

Research paper thumbnail of Indifference pricing of life insurance contracts via BSDEs under partial information

arXiv (Cornell University), Mar 31, 2018

In this paper we investigate the pricing problem of a pure endowment contract when the insurance ... more In this paper we investigate the pricing problem of a pure endowment contract when the insurance company has a limited information on the mortality intensity of the policyholder. The payoff of this kind of policies depends on the residual life time of the insured as well as the trend of a portfolio traded in the financial market, where investments in a riskless asset, a risky asset and a longevity bond are allowed. We propose a modeling framework that takes into account mutual dependence between the financial and the insurance markets via an observable stochastic process, which affects the risky asset and the mortality index dynamics. Since the market is incomplete due to the presence of basis risk, in alternative to arbitrage pricing we use expected utility maximization under exponential preferences as evaluation approach, which leads to the so-called indifference price. Under partial information this methodology requires filtering techniques that can reduce the original control problem to an equivalent problem in complete information. Using stochastic dynamics techniques, we characterize the indifference price of the insurance derivative in terms of the solutions of two backward stochastic differential equations. Finally, we discuss two special cases where we get a more explicit representation of the indifference price process.

Research paper thumbnail of On the hedging strategies for defaultable claims under incomplete information

arXiv (Cornell University), Aug 25, 2016

In this paper we investigate the hedging problem of a defaultable claim with recovery at default ... more In this paper we investigate the hedging problem of a defaultable claim with recovery at default time via the local risk-minimization approach when investors have a restricted information on the market. We assume that the stock price process dynamics depends on an exogenous unobservable stochastic factor and that at any time, investors may observe the risky asset price and know if default has occurred or not. We characterize the optimal strategy in terms of the integrand in the Galtchouk-Kunita-Watanabe decomposition of the defaultable claim with respect to the minimal martingale measure and the available information flow. Finally, we provide an explicit formula by means of predictable projection of the corresponding hedging strategy under full information with respect to the natural filtration of the risky asset price and the minimal martingale measure in a Markovian setting via filtering.

Research paper thumbnail of The Zakai equation of nonlinear filtering for jump-diffusion observation: existence and uniqueness

arXiv (Cornell University), Oct 16, 2012

This paper is concerned with the nonlinear filtering problem for a general Markovian partially ob... more This paper is concerned with the nonlinear filtering problem for a general Markovian partially observed system (X, Y), whose dynamics is modeled by correlated jump-diffusions having common jump times. At any time t ∈ [0, T ], the σ-algebra F Y t := σ{Y s : s ≤ t} provides all the available information about the signal X t. The central goal of stochastic filtering is to characterize the filter, π t , which is the conditional distribution of X t , given the observed data F Y t. It has been proved in [7] that π is the unique probability measure-valued process satisfying a nonlinear stochastic equation, the so-called Kushner-Stratonovich equation (KS-equation). In this paper the aim is to describe the filter π in terms of the unnormalized filter ̺, which is solution to a linear stochastic differential equation, the so-called Zakai equation. We prove equivalence between strong uniqueness for the solution to the Kushner Stratonovich equation and strong uniqueness for the solution to the Zakai one and, as a consequence, we deduce pathwise uniqueness for the solutions to the Zakai equation by applying the Filtered Martingale Problem approach ([25, 7]). To conclude, some particular cases are discussed.

Research paper thumbnail of Optimal reinsurance via BSDEs in a partially observable model with jump clusters

arXiv (Cornell University), Jul 12, 2022

We investigate the optimal reinsurance problem when the loss process exhibits jump clustering fea... more We investigate the optimal reinsurance problem when the loss process exhibits jump clustering features and the insurance company has restricted information about the loss process. We maximize expected exponential utility of terminal wealth and show that an optimal solution exists. By exploiting both the Kushner-Stratonovich and Zakai approaches, we provide the equation governing the dynamics of the (infinite-dimensional) filter and characterize the solution of the stochastic optimization problem in terms of a BSDE, for which we prove existence and uniqueness of solution. After discussing the optimal strategy for a general reinsurance premium, we provide more explicit results in some relevant cases.

Research paper thumbnail of Modelling the industrial production of electric and gas utilities through a stochastic three-factor model

Research paper thumbnail of Discipline: Mathématiques

pour le grade de DOCTEUR de per il titolo di DOTTORE DI RICERCA l’Université de Paris 13 dell ’ U... more pour le grade de DOCTEUR de per il titolo di DOTTORE DI RICERCA l’Université de Paris 13 dell ’ Università LUISS GUIDO CARLI

Research paper thumbnail of Une propriété forte de branchements

Nous exposons le prolongement fort de la propriete de branchements a travers une topologie sur le... more Nous exposons le prolongement fort de la propriete de branchements a travers une topologie sur les arbres

Research paper thumbnail of A Benchmark Approach to Risk-Minimization under Partial Information

In this paper we study a risk-minimizing hedging problem for a semimartingale incomplete financia... more In this paper we study a risk-minimizing hedging problem for a semimartingale incomplete financial market where d+1 assets are traded continuously and whose price is expressed in units of the numéraire portfolio. According to the so-called benchmark approach, we investigate the (benchmarked) risk-minimizing strategy in the case where there are restrictions on the available information. More precisely, we characterize the optimal strategy as the integrand appearing in the Galtchouk-Kunita-Watanabe decomposition of the benchmarked claim under partial information and provide its description in terms of the integrands in the classical Galtchouk-Kunita-Watanabe decomposition under full information via dual predictable projections. Finally, we apply the results in the case of a Markovian jump-diffusion driven market model where the assets prices dynamics depend on a stochastic factor which is not observable by investors.

Research paper thumbnail of Risk-Minimizing Hedging of Counterparty Risk

We study dynamic hedging of counterparty risk for a portfolio of credit derivatives. Our empirica... more We study dynamic hedging of counterparty risk for a portfolio of credit derivatives. Our empirically driven credit model consists of interacting default intensities which ramp up and then decay after the occurrence of credit events. Using the Galtchouk-Kunita-Watanabe decomposition of the counterparty risk price payment stream, we recover a closed-form representation for the risk minimizing strategy in terms of classical solutions to nonlinear recursive systems of Cauchy problems. We discuss applications of our framework to the most prominent class of credit derivatives, including credit swap and risky bond portfolios, as well as first-to-default claims.

Research paper thumbnail of Optimal Reduction of Public Debt under Partial Observation of the Economic Growth

We consider a government that aims at reducing the debt-to-gross domestic product (GDP) ratio of ... more We consider a government that aims at reducing the debt-to-gross domestic product (GDP) ratio of a country. The government observes the level of the debt-to-GDP ratio and an indicator of the state of the economy, but does not directly observe the development of the underlying macroeconomic conditions. The government's criterion is to minimize the sum of the total expected costs of holding debt and of debt's reduction policies. We model this problem as a singular stochastic control problem under partial observation. The contribution of the paper is twofold. Firstly, we provide a general formulation of the model in which the level of debt-to-GDP ratio and the value of the macroeconomic indicator evolve as a diffusion and a jump-diffusion, respectively, with coefficients depending on the regimes of the economy. These are described through a finite-state continuous-time Markov chain. We reduce via filtering techniques the original problem to an equivalent one with full informati...

Research paper thumbnail of The Föllmer-Schweizer decomposition under incomplete information

In this paper we study the Föllmer-Schweizer decomposition of a square integrable random variable... more In this paper we study the Föllmer-Schweizer decomposition of a square integrable random variable ξ with respect to a given semimartingale S under restricted information. Thanks to the relationship between this decomposition and that of the projection of ξ with respect to the given information flow, we characterize the integrand appearing in the Föllmer-Schweizer decomposition under partial information in the general case where ξ is not necessarily adapted to the available information level. For partially observable Markovian models where the dynamics of S depends on an unobservable stochastic factor X, we show how to compute the decomposition by means of filtering problems involving functions defined on an infinite-dimensional space. Moreover, in the case of a partially observed jump-diffusion model where X is described by a pure jump process taking values in a finite dimensional space, we compute explicitly the integrand in the Föllmer-Schweizer decomposition by working with finit...

Research paper thumbnail of Value adjustments and dynamic hedging of reinsurance counterparty risk

Reinsurance counterparty credit risk (RCCR) is the risk of a loss arising from the fact that a re... more Reinsurance counterparty credit risk (RCCR) is the risk of a loss arising from the fact that a reinsurance company is unable to fulfill her contractual obligations towards the ceding insurer. RCCR is an important risk category for insurance companies which, so far, has been addressed mostly via qualitative approaches. In this paper we therefore study value adjustments and dynamic hedging for RCCR. We propose a novel model that accounts for contagion effects between the default of the reinsurer and the price of the reinsurance contract. We characterize the value adjustment in a reinsurance contract via a partial integro-differential equation (PIDE) and derive the hedging strategies using a quadratic method. The paper closes with a simulation study which shows that dynamic hedging strategies have the potential to significantly reduce RCCR.

Research paper thumbnail of Li ce nse d unde r the Cre at ive Commons Att ri but ion Noncomme rci al N o De rivati ves RISK MINIMIZING HEDGING IN A PARTIALLY OBSERVED HIGH FREQUENCY DATA MODEL: A FILTERING APPROACH

Risk-minimizing hedging strategies for contingent claims are studied in a general model for intra... more Risk-minimizing hedging strategies for contingent claims are studied in a general model for intraday stock price movements in the case of partial information. The dynamics of the risky asset price is described throught a marked point process Y, whose local characteristics depend on some unobservable hidden state variable X, described by a jump-diffusion process. In the model presented the processes Y and X may have common jump times, which means that the trading activity may affect the law of X and could be also related to the presence of catastrophic events. The hedger is restricted to observing past asset prices. Thus we are in presence not only of an incomplete market situation but also of partial information. Assuming that the price of the risky asset is modeled directly under a martingale measure, the computation of the risk-minimizing hedging strategy under this partial information leads to a filtering problem with marked point process observations. The conditional law of X gi...

Research paper thumbnail of Hedging of unit-linked life insurance contracts with unobservable mortality hazard rate via local risk-minimization

In this paper we investigate the local risk-minimization approach for a combined financial-insura... more In this paper we investigate the local risk-minimization approach for a combined financial-insurance model where there are restrictions on the information available to the insurance company. In particular we assume that, at any time, the insurance company may observe the number of deaths from a specific portfolio of insured individuals but not the mortality hazard rate. We consider a financial market driven by a general semimartingale and we aim to hedge unit-linked life insurance contracts via the local risk-minimization approach under partial information. The F\"ollmer-Schweizer decomposition of the insurance claim and explicit formulas for the optimal strategy for pure endowment and term insurance contracts are provided in terms of the projection of the survival process on the information flow. Moreover, in a Markovian framework, we reduce to solve a filtering problem with point process observations.

Research paper thumbnail of 4 Hedging of Unit-Linked Life Insurance Contracts with Unobservable Mortality Hazard Rate via Local Risk-Minimization

In this paper we investigate the local risk-minimization approach for a combined financial-insura... more In this paper we investigate the local risk-minimization approach for a combined financial-insurance model where there are restrictions on the information available to the insurance company. In particular we assume that, at any time, the insurance company may observe the number of deaths from a specific portfolio of insured individuals but not the mortality hazard rate. We consider a financial market driven by a general semimartingale and we aim to hedge unit-linked life insurance contracts via the local risk-minimization approach under partial information. The Föllmer-Schweizer decomposition of the insurance claim and explicit formulas for the optimal strategy for pure endowment and term insurance contracts are provided in terms of the projection of the survival process on the information flow. Moreover, in a Markovian framework, we reduce to solve a filtering problem with point process observations.