A Simulation Analysis of the Microstructure of an Order Driven Financial Market with Multiple Securities and Portfolio Choices

2005

In this paper we propose an artificial market where multiple risky assets are exchanged. Agents are constrained by the availability of resources and trade to adjust their portfolio according to an exogenously given target portfolio. We model the trading mechanism as a continuous auction order-driven market. Agents are heterogeneous in terms of desired target portfolio allocations, but they are homogeneous in terms of trading strategies. We investigate the role played by the trading mechanism in affecting the dynamics of prices, trading volume and volatility. We show that the institutional setting of a double auction market is sufficient to generate a non-normal distribution of price changes…

Non-Gaussian Distribution for Var Calculation

2003

Publisher Summary This chapter compares different approaches to computing Value-at-Risk (VaR) for heavy tailed return series. Each model has been submitted to a backtest analysis. The most representative asset returns of the Italian stock market and the exchange rates for the major currencies are used. The results obtained confirm that when the percentiles are below 5%, the hypothesis of normality of the conditional return distribution determines intervals of confidence whose forecast ability is low. In fact, it is observed that the return distributions are asymmetric and leptokurtic and the hypothesis of normality is usually rejected when subject to statistical test. Among the alternative …

Designing Guarantee Options in Defined Contribution Pension Plans

2015

The shift from defined benefit (DB) to defined contribution (DC) is pervasive among pension funds, due to demographic changes and macroeconomic pressures. In DB all risks are borne by the provider, while in plain vanilla DC all risks are borne by the beneficiary. For DC to provide income security some kind of guarantee is required. A minimum guarantee clause can be modeled as a put option written on some underlying reference portfolio of assets and we develop a discrete model that optimally selects the reference portfolio to minimise the cost of a guarantee. While the relation DB-DC is typically viewed as a binary one, the model can be used to price a wide range of guarantees creating a con…

A model for designing callable bonds and its solution using tabu search

1997

Abstract We formulate the problem of designing callable bonds as a non-linear, global, optimization problem. The data of the model are obtained from simulations of holding-period returns of a given bond design, which are used to compute a certainty equivalent return, viz., some target assets. The design specifications of the callable bond are then adjusted so that the certainty equivalent return is maximized. The resulting problem is multi-modal, and a tabu search procedure, implemented on a distributed network of workstations, is used to optimize the bond design. The model is compared with the classical portfolio immunization model, and the tabu search solution technique is compared with s…

Risk Management for Sovereign Debt Financing with Sustainability Conditions

2019

We develop a model of debt sustainability analysis with optimal financing decisions in the presence of macroeconomic, financial and fiscal uncertainty. We define a coherent measure of refinancing risk, and trade off the risks of debt stock and flow dynamics, subject to debt sustainability constraints and endogenous risk and term premia. We optimize both static and dynamic financing strategies, compare them with several simple rules and consol financing to demonstrate economically significant effects of optimal financing, and show that the stock-flow tradeoff can be critical for sustainability. We quantify the minimum refinancing risk and the maximum rate of debt reduction that a sovereign c…

VALUTAZIONE E COPERTURA DI OPZIONI SU MATERIE PRIME

2013

Tramite un modello di super-replication è possibile costruire un portafoglio composto da titoli liquidi per coprire la basket option sul mix produttivo di argento ed oro. Il prezzo non è molto differente da quello di Black & Scholes, le cui ipotesi però rendono impossibile l’implementazione della copertura.

Stochastic debt sustainability analysis for sovereigns and the scope for optimization modeling

2017

We express the opinion that sovereign debt sustainability analysis must be augmented by stochastic correlated risk factors and a risk measure to capture tail effects. Crisis situations can thus be adequately specified and analyzed with sufficient accuracy to warrant the relevance of policy decisions. In this context there is significant scope for optimization modeling for both strategic planning and operational management. We discuss diverse aspects of the problem of debt sustainability and highlight modeling approaches that can be brought to bear on the problem. Results with the fictitiuous, but nor unrealistic, Kingdom of Atlantis, which is sinking under excessive debt, illustrate the pro…

Breakup and Default Risks in the Eurozone

2019

In this paper, we exploit CDS quotes for contracts denominated in different currencies and with different default clauses to estimate the risk of a breakup of the Eurozone and the propagation of breakup and default risks after the COVID-19 shock. Our main result is that the risk of a Eurozone breakup is significant although, quantitatively, it is not larger than in the period before the COVID-19 shock. In addition, we find that an increase in the redenomination risk in one country is associated with an increase in default premia and bond spreads in other Eurozone countries. Finally, we find that a sizeable fraction of the changes in the cost of insuring against redenomination and default re…

An Introduction to the GAMS Modeling System

2010

The Case for Contingent Convertible Debt for Sovereigns

2015

We make the case for sovereigns to issue contingent convertible bonds as a means to forestall debt crises. These instruments contractually stipulate payment standstill, contingent on a sovereign’s credit default swap spread breaching a distress threshold. This is a financial innovation solution to the lack of sovereign debt restructuring mechanisms, limiting ex ante the likelihood of debt crises and imposing ex post risk sharing between creditors and the debtor. The new instruments are contingent contracts addressing neglected risks in sovereign debt. Building on literature for contingent convertible debt for banks we address the design of sovereign contingent debt, including market discipl…

Designing and pricing guarantee options in defined contribution pension plans

2015

Abstract The shift from defined benefit (DB) to defined contribution (DC) is pervasive among pension funds, due to demographic changes and macroeconomic pressures. In DB all risks are borne by the provider, while in plain vanilla DC all risks are borne by the beneficiary. However, for DC to provide income security some kind of guarantee is required. A minimum guarantee clause can be modeled as a put option written on some underlying reference portfolio and we develop a discrete model that selects the reference portfolio to minimize the cost of a guarantee. While the relation DB–DC is typically viewed as a binary one, the model shows how to price a wide range of guarantees creating a continu…

Risk management optimization for sovereign debt restructuring

2015

Debt restructuring is one of the policy tools available for resolving sovereign debt crises and, while unorthodox, it is not uncommon. We propose a scenario analysis for debt sustainability and integrate it with scenario optimization for risk management in restructuring sovereign debt. The scenario dynamics of debt-to-GDP ratio are used to define a tail risk measure, termed "conditional Debt-at-Risk". A multi-period stochastic programming model minimizes the expected cost of debt financing subject to risk limits. It provides an operational model to handle significant aspects of debt restructuring: it collects all debt issues in a common framework, and can include contingent claims, multiple…

Dynamic Portfolio Optimization with Stochastic Programming

2010

A Stochastic Programming Model for the Optimal Issuance of Government Bonds

2010

Sovereign states issue fixed and floating securities to fund their public debt. The value of such portfolios strongly depends on the fluctuations of the term structure of interest rates. This is a typical example of planning under uncertainty, where decisions has to be drawn on the base of the key stochastic economic factors underneath the model.We propose a multistage stochastic programming model to select portfolios of bonds, where the aim of the decision maker is that of minimizing the cost of the decision process. At the same time, we bound the conditional Value-at-Risk, a measure of risk which accounts for the losses of the tail distribution. We build an efficient frontier to trade-off…

Pricing and Hedging GDP-Linked Bonds in Incomplete Markets

2017

We model the super-replication of payoffs linked to a country's GDP as a stochastic linear program on a discrete time and state-space scenario tree to price GDP-linked bonds. As a byproduct of the model, we obtain a hedging portfolio. Using linear programming duality we also compute the risk premium. The model applies to coupon-indexed and principal-indexed bonds, and allows the analysis of bonds with different design parameters (coupon, target GDP growth rate, and maturity). We calibrate for UK and US instruments and carry out a sensitivity analysis of prices and risk premia to the risk factors and bond design parameters. We also compare coupon-indexed and principal-indexed bonds. Results …

Integrated simulation and optimization models for tracking international fixed income indices

2001

Portfolio managers in the international fixed income markets must address jointly the interest rate risk in each market and the exchange rate volatility across markets. This paper develops integrated simulation and optimization models that address these issues in a common framework. Monte Carlo simulation procedures generate jointly scenarios of interest and exchange rates and, thereby, scenarios of holding period returns of the available securities. The portfolio manager’s risk tolerance is incorporated either through a utility function or a (modified) mean absolute deviation function. The optimization models prescribe asset allocation weights among the different markets and also resolve b…

Political risks: the “red shift” in debt sustainability analysis

2020

Political stability and economic policy uncertainty can be key determinants of sovereign debt dynamics, and we show how they can be incorporated in debt sustainability analysis. We distinguish between short-term ambiguity and long-term uncertainty about political risk factors, and using a combination of narrative scenarios and calibrated probabilistic scenarios we obtain a comprehensive heatmap of high-risk debt dynamics. We use Italy as an interesting case study and demonstrate a “red shift” in the assessment of vulnerabilities when accounting for political risks. Ignoring these risks can lead to excessive optimism and wrong decisions.

Mean‐Variance Portfolio Optimization

2010

Learning and the Price Dynamics of a Double-Auction Financial Market with Portfolio Traders

2006

In this paper we study the dynamics of price adjustments in an artificial market where portfolio traders with bounded rationality and limited resources interact through a continuous, electronic open book. The present work extends the model developed in [? ] introducing endogenous target individual portfolio holdings. We model the agents’ order-flow investment decision as an optimal choice given individual characteristics and the available information. We depart from the standard asset pricing framework in two ways. First, we assume that investors have imperfect information about the returns distribution. In particular, we assume that agents hold arbitrary priors about securities’ returns, w…

How to control stock markets

1994

This paper provides a different approach to the analysis of imperfect stock markets. The model we are concerned with is described by the interaction of three institutional classes of agents (the specialist trader, the professional trader and the non-professional trader), sharing different information. The dynamical discrete-time system obtained can be changed into a second-order linear difference equation forced by the fundamental value of the specialist trader. Using typical tools of control theory, we study the behaviour of the professional trader’s fundamental value influenced by the specialist’s one. © 1994 Taylor & Francis Group, LLC.

Risk profiles for re-profiling sovereign debt

2015

Purpose – This paper aims to use a risk management approach for re-profiling of sovereign debt. It develops profiles that trade off expected cost of financing alternative debt structures against their risk. The risk profiles are particularly informative for countries facing sovereign debt crisis, as they allow us to identify, with high probability, debt unsustainability. Risk profiles for two eurozone countries with excessive debt, Cyprus and Italy, were developed. In addition, risk profiles were developed for a proposal to impose debt sanctions in the Ukrainian crisis and it was shown that the financial impact could be substantial. Design/methodology/approach – Using scenario analysis, a r…

Evaluation of Insurance Products with Guarantee in Incomplete Markets

2008

Abstract Life insurance products are usually equipped with minimum guarantee and bonus provision options. The pricing of such claims is of vital importance for the insurance industry. Risk management, strategic asset allocation, and product design depend on the correct evaluation of the written options. Also regulators are interested in such issues since they have to be aware of the possible scenarios that the overall industry will face. Pricing techniques based on the Black & Scholes paradigm are often used, however, the hypotheses underneath this model are rarely met. To overcome Black & Scholes limitations, we develop a stochastic programming model to determine the fair price of the mini…

Simulating Term Structure of Interest Rates with Arbitrary Marginals

2007

Decision models under uncertainty need to be feeded with scenarios of the interest rate curve. Such scenarios have to comply, as close as possible, with the empirical distribution of each rate. Simulation models of the term structure usually assume that the conjugate distribution of the interest rates is lognormal. Dynamic models, like vector auto-regression, implicitly postulate that the logarithm of the interest rates is normally distributed. Statistical analyses have, however, shown that stationary transformations (yield changes) of the interest rates are substantially leptokurtic, thus posing serious doubts on the reliability of the available models. We propose in this paper a vector au…

Asset and Liability Management for Insurance Products with Minimum Guarantees: The UK Case

2006

Abstract Modern insurance products are becoming increasingly complex, offering various guarantees, surrender options and bonus provisions. A case in point are the with-profits insurance policies offered by UK insurers. While these policies have been offered in some form for centuries, in recent years their structure and management have become substantially more involved. The products are particularly complicated due to the wide discretion they afford insurers in determining the bonuses policyholders receive. In this paper, we study the problem of an insurance firm attempting to structure the portfolio underlying its with-profits fund. The resulting optimization problem, a non-linear program…

Breakup and default risks in the great lockdown

2023

Abstract In this paper, we exploit CDS quotes for contracts denominated in different currencies and with different default clauses to estimate the risk of a breakup of the Eurozone and the propagation of breakup and default risks after the COVID-19 shock. Our main result is that the risk of a Eurozone breakup is significant although, quantitatively, it is not larger than in the period before the COVID-19 shock. In addition, we find that an increase in the redenomination risk in one country is associated with an increase in default premia and bond spreads in other Eurozone countries. Finally, we find that a sizeable fraction of the changes in the cost of insuring against redenomination and d…

Insurance league: Italy vs. U.K

2003

Insurers are competing by adopting product innovations that provide the insured with integrated coverage for actuarial and financial risks. This article compares the contract structures of blended life policies between the insurance markets in Italy and the United Kingdom within the context of asset-liability management and welfare analysis. © Emerald Backfiles 2007.

Pricing Sovereign Contingent Convertible Debt

2016

We develop a pricing model for sovereign contingent convertible bonds (S-CoCo) with payment standstills triggered by a sovereign's credit default swap CDS spread. One innovation is the modeling of CDS spread regime switching which is prevalent during crises. Regime switching is modeled as a hidden Markov process and is integrated with a stochastic process of spread levels to obtain S-CoCo prices through simulation. The paper goes a step further and uses the pricing model in a Longstaff-Schwartz. American option pricing framework to compute state contingent S-CoCo prices at some risk horizon, thus facilitating risk management. Dual trigger pricing is also discussed using the idiosyncratic CD…

Pricing sovereign contingent convertible debt

2018

We develop a pricing model for Sovereign Contingent Convertible bonds (S-CoCo) with payment standstills triggered by a sovereign's Credit Default Swap (CDS) spread. We model CDS spread regime switching, which is prevalent during crises, as a hidden Markov process, coupled with a mean-reverting stochastic process of spread levels under fixed regimes, in order to obtain S-CoCo prices through simulation. The paper uses the pricing model in a Longstaff-Schwartz American option pricing framework to compute future state contingent S-CoCo prices for risk management. Dual trigger pricing is also discussed using the idiosyncratic CDS spread for the sovereign debt together with a broad market index. …

Risk Management for Sovereign Financing within a Debt Sustainability Framework

2018

The mix of instruments used to finance a sovereign is a key determinant of debt sustainability through its effect on funding costs and risks. We extend standard debt sustainability analysis to incorporate debt-financing decisions in the presence of macroeconomic, financial, and fiscal risks. We optimize the maturity of debt instruments to trade off borrowing costs with refinancing risk. Risk is quantified with a coherent measure of tail risk of financing needs, conditional Flow-at-Risk. A constraint on the pace of reduction of debt stocks is also imposed, and we model the effect of debt stocks on the yield curve through endogenous risk and term premia. On a simulated economy, we show that t…

A High-Frequency Data Analysis of a Double Auction Artificial Financial Market

2004

Risk Profiles for Re-Profiling the Sovereign Debt of Crisis Countries

2014

This paper uses a risk-management approach to re-profile the sovereign debt of countries facing debt crises. Using scenario analysis we develop a risk measure of the sovereign's debt -- Conditional Debt-at-Risk -- and an optimization model is used to trace risk profiles that tradeoff expected cost of debt financing against the Conditional Debt-at-Risk. The risk profiles are particularly informative for crisis countries, as they allow us to identify, with high-probability, debt unsustainability. We develop risk profiles for two Eurozone countries with excessive debt, Cyprus and Italy, both in their current form and under various forms of restructuring or rescheduling, and show how to assess …

The prometeia model for managing insurance policies with guarantees

2008

Publisher Summary This chapter discusses the development of a scenario-based optimization model for asset and liability management for the participating policies with guarantees and bonus provisions offered by Italian insurers. The changing landscape of the financial services in Italy sets the backdrop for the development of this system which was the result of a multi-year collaborative effort between academic researchers, the research staff at Prometeia in Bologna, and end-users from diverse Italian insurers. It also presents and discusses the model and its key feature, and introduces several extensions. The resulting system allows the analysis of the tradeoffs facing an insurance firm in …

The Dynamics of Quote Prices in an Artificial Financial Market with Learning Effects

2007

In this paper we study the evolution of bid and ask prices in an electronic financial market populated by portfolio traders who optimally choose their allocation strategy on the basis of their views about market conditions. Recently, a growing literature has investigated the consequences of learning about the returns process1. There has been an increasing interest in analyzing what are the implications of relaxing the assumption that agents hold correct expectations. In particular, it has been asked the fundamental question of understanding if typical asset-pricing anomalies (like returns predictability, and excess volatility) can be generated by a learning process about the underlying econ…

Risk Management Optimization for Sovereign Debt Restructuring

2015

Abstract Debt restructuring is one of the policy tools available for resolving sovereign debt crises and, while unorthodox, it is not uncommon. We propose a scenario analysis for debt sustainability and integrate it with scenario optimization for risk management in restructuring sovereign debt. The scenario dynamics of debt-to-GDP ratio are used to define a tail risk measure, termed conditional Debt-at-Risk. A multi-period stochastic programming model minimizes the expected cost of debt financing subject to risk limits. It provides an operational model to handle significant aspects of debt restructuring: it collects all debt issues in a common framework, and can include contingent claims, m…

Non-Gaussian Distribution for Var Calculation: an Assessment for the Italian Market

2001

Abstract In this paper we compare different approaches to computing VaR (Value-at-Risk) for heavy tailed return series. Using data from the Italian market, we show that almost all the return series present statistically significant skewness and kurtosis. We implement (i) the stable models proposed by Rachev et al . (2000), (ii) an alternative to the Gaussian distributions based on a Generalized Error Distribution and (iii) a non-parametric model proposed by Li (1999). All the models are then submitted to backtest on out-of-sample data in order to assess their forecasting power. We observe that when the percentiles are low, all the models tested produce results that are dominant compared to …

Practical Financial Optimization: A Library of GAMS Models

2010

In Practical Financial Optimization: A Library of GAMS Models, the authors provide a diverse set of models for portfolio optimization, based on the General Algebraic Modelling System. 'GAMS' consists of a language which allows a high-level, algebraic representation of mathematical models and a set of solvers --- numerical algorithms --- to solve them. The system was developed in response to the need for powerful and flexible front-end tools to manage large, real-life models. The work begins with an overview of the structure of the GAMS language, and discusses issues relating to the management of data in GAMS models. The authors provide models for mean-variance portfolio optimization which a…

A Conditional Value–at–Risk Model for Insurance Products with Guarantee

2009

We propose a model to select the optimal portfolio which underlies insurance policies with a guarantee. The objective function is defined in order to minimise the conditional value at-risk (CVaR) of the distribution of the losses with respect to a target return. We add operational and regulatory constraints to make the model as flexible as possible when used for real applications. We show that the integration of the asset and liability side yields superior performances with respect to naive fixed-mix portfolios and asset based strategies. We validate the model on out-of-sample scenarios and provide insights on policy design.

Portfolio diversification in the sovereign credit swap markets

2018

We develop models for portfolio diversification in the sovereign credit default swaps (CDS) markets and show that, despite literature findings that sovereign CDS spreads are affected by global factors, there is sufficient idiosyncratic risk to be diversified. However, we identify regime switching in the times series of CDS spreads and spread returns, and the optimal diversified strategies can be regime dependent. The developed models trade off the CVaR risk measure against expected return, consistently with the statistical properties of spreads. We consider three investment strategies suited for different CDS market participants: for investors with long positions, speculators that hold unco…

Pricing the Option to Surrender in Incomplete Markets

2010

New international accounting standards require insurers to reflect the value of embedded options and guarantees in their products. Pricing techniques based on the Black and Scholes paradigm are often used; however, the hypotheses underneath this model are rarely met. We propose a framework that encompasses the most known sources of incompleteness. We show that the surrender option, joined with a wide range of claims embedded in insurance contracts, can be priced through our tool, and deliver hedging portfolios to mitigate the risk arising from their positions. We provide extensive empirical analysis to highlight the effect of incompleteness on the fair value of the option.

High-Frequency Data Analysis of a Double Auction Artificial Financial Market

2004

Stochastic debt sustainability analysis for sovereigns and the scope for optimization modeling

2017

We argue that sovereign debt sustainability analysis must be augmented by stochastic correlated risk factors and a risk measure to capture tail effects. Crisis situations can thus be adequately specified and analyzed with sufficient accuracy to warrant the relevance of policy decisions. In this context there is significant scope for optimization modeling for both strategic planning and operational management. We discuss diverse aspects of the problem of debt sustainability and highlight modeling approaches that can be brought to bear on the problem. Results with the fictitious, but nor unrealistic, Kingdom of Atlantis, which is sinking under excessive debt, illustrate the proposed models.

Pricing and hedging GDP-linked bonds in incomplete markets

2018

Abstract We model the super-replication of payoffs linked to a country’s GDP as a stochastic linear program on a discrete time and state-space scenario tree to price GDP-linked bonds. As a byproduct of the model we obtain a hedging portfolio. Using linear programming duality we compute also the risk premium. The model applies to coupon-indexed and principal-indexed bonds, and allows the analysis of bonds with different design parameters (coupon, target GDP growth rate, and maturity). We calibrate for UK and US instruments, and carry out sensitivity analysis of prices and risk premia to the risk factors and bond design parameters. We also compare coupon-indexed and principal-indexed bonds. F…

Contingent convertible bonds for sovereign debt risk management

2015

We consider convertible bonds that contractually stipulate payment standstill, contingent on a market indicator of a sovereign's creditworthiness breaching a distress threshold. This financial innovation limits ex-ante the likelihood of debt crises and imposes ex-post risk sharing between creditors and the debtor. Drawing from literature on contingent contracts, neglected risks, and bank CoCo, we extend prevailing arguments in favor of sovereign CoCo (S-CoCo). We discuss issues relating to their design: which market trigger, market discipline and sovereign incentives, and errors of false alarms or missed crises, and provide supporting evidence with eurozone data and a simple simulation on t…

Asset Return Dynamics under Alternative Learning Schemes

2009

In this paper we design an artificial financial market where endogenous volatility is created assigning to the agents diverse prior beliefs about the joint distribution of returns, and, over time, making agents rationally update their beliefs using common public information. We analyze the asset price dynamics generated under two learning environments: one where agents assume that the joint distribution of returns is IID, and another where agents believe in the existence of regimes in the joint distribution of asset returns. We show that the regime switching learning structure can generate all the most common stylized facts of financial markets: fat tails and long-range dependence in volati…

Portfolio Models for Fixed Income

2010

Case Studies in Financial Optimization

2010

Auditing Public Debt Using Risk Management

2023

The Audit Office of the Republic of Cyprus conducted the first-ever audit of the country’s public debt, seeking answers to two key questions. Is government debt sustainable, and is debt financing efficient and effective in securing the lowest cost with acceptable risks? The audit’s findings were discussed by the parliament and can have significant ramifications for public finance. However, public debt management is quite complex, and the International Organization of Supreme Audit Institutions suggests that sufficient technical knowledge is essential in undertaking an audit, including an understanding of the uncertain macroeconomy, financing conditions, and government fiscal stance. We use…

Pricing Reinsurance Contracts

2011

Pricing and hedging insurance contracts is hard to perform if we subscribe to the hypotheses of the celebrated Black and Scholes model. Incomplete market models allow for the relaxation of hypotheses that are unrealistic for insurance and reinsurance contracts. One such assumption is the tradeability of the underlying asset. To overcome this drawback, we propose in this chapter a stochastic programming model leading to a superhedging portfolio whose final value is at least equal to the insurance final liability. A simple model extension, furthermore, is shown to be sufficient to determine an optimal reinsurance protection for the insurer: we propose a conditional value at risk (VaR) model p…

Risk Management for Sustainable Sovereign Debt Financing

2021

We model sovereign debt sustainability with optimal financing decisions under macroeconomic, financial, and fiscal uncertainty, with endogenous risk and term premia. Using a coherent risk measure we trade-off debt stock and flow risks subject to sustainability constraints. We optimize static and dynamic financing strategies and demonstrate economically significant savings from optimal financing compared with simple rules and consols, and find that optimizing the trade-offs can be critical for sustainability. The model quantifies minimum refinancing risk and maximum rate of debt reduction that a sovereign can achieve given its economic fundamentals, and an extension identifies optimal timing…

Designing portfolios of financial products via integrated simulation and optimization models

1999

We analyze the problem of debt issuance through the sale of innovative financial products. The problem is broken down to questions of designing the financial products, specifying the debt structure with the amount issued in each product, and determining an optimal level of financial leverage. We formulate a hierarchical optimization model to integrate these three issues and provide constructive answers. Input data for the models are obtained from Monte Carlo simulation procedures that generate scenarios of holding period returns of the designed products. The hierarchical optimization model is specialized for the problem of issuing a portfolio of callable bonds to fund mortgage assets. The …

A MULTISTAGE DECISION MODEL FOR THE OPTIMAL ISSUANCE OF SOVEREIGN DEBT UNDER ESA95

2014

The aim of this paper is to develop a stochastic programming model for the optimal composition of debt portfolios. Such a prob- lem has recently acquired a more and more major interest, being the indebtedness of many countries quite worrying. We propose a stochastic programming model where the decision maker desires to minimize a certain cost function while bounding the interest rate risk. Our analysis focus mainly on the cost function ESA95, which is a methodology developed by the European System of Accounts to gauge the cost of servicing the debt. The model is implemented under two financing strategies, one as- sumes the government cannot resort to budget surplus to pay interest expenses,…

A parsimonious model for generating arbitrage-free scenario trees

2016

Simulation models of economic, financial and business risk factors are widely used to assess risks and support decision-making. Extensive literature on scenario generation methods aims at describing some underlying stochastic processes with the least number of scenarios to overcome the ‘curse of dimensionality’. There is, however, an important requirement that is usually overlooked when one departs from the application domain of security pricing: the no-arbitrage condition. We formulate a moment matching model to generate multi-factor scenario trees for stochastic optimization satisfying no-arbitrage restrictions with a minimal number of scenarios and without any distributional assumptions.…

www.Personal_Asset_Allocation.

2004

Today consumers demand delivery of financial services anytime and anywhere, and their needs and desires are evolving rapidly. The World Wide Web provides a rich channel for distributing customized services to a range of clients. An Internet-based system developed by Prometeia S.r.l. for Italian banks—both traditional and e-banks—supports consumers and financial advisors in planning personal finances. The system provides advice on allocating personal assets to fund consumers' needs, such as paying for a house, children's education, retirement, or other projects. State-of-the-art models of financial engineering—based on scenario optimization—develop plans that are consistent with clients' go…

Contingent Convertible Bonds for Sovereign Debt Risk Management

2018

Abstract We consider convertible bonds that contractually stipulate payment standstill, contingent on a market indicator of a sovereign’s credit worthiness breaching a distress threshold. This financial innovation limits ex ante the likelihood of debt crises and imposes ex post risk sharing between creditors and the debtor. Drawing from literature on contingent contracts, neglected risks, and bank CoCo, we extend prevailing arguments in favor of sovereign CoCo (S-CoCo). We discuss issues relating to their design: which market trigger, market discipline and sovereign incentives, and errors of false alarms or missed crises, and provide supporting evidence with eurozone data and a simple simul…

The value of integrative risk management for insurance products with guarantees

2001

Insurance liabilities are converging with capital markets products (e.g. derivatives and securitizations), thereby increasing the demand for integrated asset and liability management strategies. This article compares the value-added by an integrative approach-based on scenario optimization modelling-relative to traditional risk management methods. The authors present some examples of products offered by the insurance industry in Italy, and apply the results of the analysis to the design of competitive insurance policies. © Emerald Backfiles 2007.

Insurance fraud detection: A statistically validated network approach

2022

Fraud is a social phenomenon, and fraudsters often collaborate with other fraudsters, taking on different roles. The challenge for insurance companies is to implement claim assessment and improve fraud detection accuracy. We developed an investigative system based on bipartite networks, highlighting the relationships between subjects and accidents or vehicles and accidents. We formalize filtering rules through probability models and test specific methods to assess the existence of communities in extensive networks and propose new alert metrics for suspicious structures. We apply the methodology to a real database-the Italian Antifraud Integrated Archive-and compare the results to out-of-sam…

Un Modello di Massima Copertura della Domanda per l’Allocazione Ottima delle Ciclostazioni di AMAT

2018

AMAT Palermo S.p.A. is the public transport company of the municipality of Palermo. AMAT manages the bike sharing system and within a sustainable mobility project has involved the DSEAS and four secondary schools to the research project “GoToSchool”, a project whose main aim is to foster the use of the bike by the students in getting to the school.The project developed in two phases: the first phase was devoted to the estimate of the demand of bike sharing service from the students; the second phase was committed to the study of an optimal facility allocation problem in order to maximize the demand of bike sharing service arising from students.The optimization model can be easily customized…

How does learning affect market liquidity? A simulation analysis of a double-auction financial market with portfolio traders

2007

We study the relationship between liquidity and prices in an artificial financial market where portfolio traders with limited resources interact through a continuous, electronic open book. We depart from the standard asset pricing framework in two ways. First, we assume that investors have incomplete information about the distribution of returns. Second, we model the portfolio choice problem using prospect-type preferences. We model the utility function in terms of deviations of the portfolio growth rate from a specified target growth rate, and we assume that investors are more sensitive to downside movements. We show that the parameters defining the learning process affect the price dynami…

Simulating term structure of interest rates with arbitrary marginals

2011

Decision models under uncertainty rely their analysis on scenarios of the economic factors. A key economic factor is the term structure of interest rates (yields). Simulation models of the yield curve usually assume that the conjugate distribution of the interest rates is lognormal. Dynamic models, like vector auto-regression, implicitly postulate that the logarithm of the interest rates is normally distributed. Statistical analyses have, however, shown that stationary transformations (yield changes) of the interest rates are substantially leptokurtic, thus posing serious doubts on the reliability of the available models. We propose in this paper a VARTA model (Biller and Nelson, 2003) to s…

Scenario modeling for the management of international bond portfolios

1998

We address the problem of portfolio management in the international bond markets. Interest rate risk in the local market, exchange rate volatility across markets, and decisions for hedging currency risk are integral parts of this problem. The paper develops a stochastic programming optimization model for integrating these decisions in a common framework. Monte Carlo simulation procedures, calibrated using historical observations of volatility and correlation data, generate jointly scenarios of interest and exchange rates. The decision maker's risk tolerance is incorporated through a utility function, and additional views on market outlook can also be incorporated in the form of user specifi…

Generating Multi-Asset Arbitrage-Free Scenario Trees with Global Optimization

2013

Simulation models of economic, financial and business risk factors are widely used to assess risks and support decision-making. Extensive literature on scenario generation methods aims at describing some underlying stochastic processes with the least number of scenarios to overcome the "curse of dimensionality". There is, however, an important requirement that is usually overlooked when one departs from the application domain of security pricing: the no-arbitrage condition. We formulate a moment matching model to generate multi-factor scenario trees satisfying no-arbitrage restrictions with a minimal number of scenarios and without any distributional assumptions. The resulting global optimi…

Scenario optimization asset and liability modelling for individual investors

2006

We develop a scenario optimization model for asset and liability management of individual investors. The individual has a given level of initial wealth and a target goal to be reached within some time horizon. The individual must determine an asset allocation strategy so that the portfolio growth rate will be sufficient to reach the target. A scenario optimization model is formulated which maximizes the upside potential of the portfolio, with limits on the downside risk. Both upside and downside are measured vis- `a-vis the goal. The stochastic behavior of asset returns is captured through bootstrap simulation, and the simulation is embedded in the model to determine the optimal portfolio. …

Asset and Liability Modelling for Participating Policies with Guarantee

2008

We study the problem of asset and liability management of participating insurance policies with guarantees. We develop a scenario optimization model for integrative asset and liability management, analyze the tradeoffs in structuring such policies, and study alternative choices in funding them. The nonlinearly constrained optimization model can be linearized through closed form solutions of the dynamic equations. Thus large-scale problems are solved with standard methods. We report on an empirical analysis of policies offered by Italian insurers. The optimized model results are in general agreement with current industry practices. However, some inefficiencies are identified and potential im…

A Simulation Analysis of the Microstructure of an Order Driven Financial Market with n Securities and Portfolio Choices

2004