Model Dependency of the Digital Option Replication – Replication under an Incomplete Model (in English)

The paper focuses on the replication of digital options under an incomplete model. Digital options are regularly applied in the hedging and static decomposition of many path-dependent options. The author examines the performance of static and dynamic replication. He considers the case of a market agent for whom the right model of the underlying asset-price evolution is not available. The observed price dynamic is supposed to follow four distinct models: (i) the Black and Scholes model, (ii) the Black and Scholes model with stochastic volatility driven by Hull and White model, (iii) the variance gamma model, defined as time changed Brownian motion, and (iv) the variance gamma model set in a stochastic environment modelled as the rate of time change via a Cox-Ingersoll-Ross model. Both static and dynamic replication methods are applied and examined within each of these settings. The author verifies the independence of the static replication on underlying processes.digital options, dynamic and static replication, internal time, Lévy models, replication error, stochastic environment, stochastic volatility, variance gamma process

The Variance Gamma (VG) Model with Long Range Dependence

This thesis mainly builds on the Variance Gamma (VG) model for financial assets over time of Madan & Seneta (1990) and Madan, Carr & Chang (1998), although the model based on the t distribution championed in Heyde & Leonenko (2005) is also given attention. The primary contribution of the thesis is the development of VG models, and the extension of t models, which accommodate a dependence structure in asset price returns. In particular it has become increasingly clear that while returns (log price increments) of historical financial asset time series appear as a reasonable approximation of independent and identically distributed data, squared and absolute returns do not. In fact squared and absolute returns show evidence of being long range dependent through time, with autocorrelation functions that are still significant after 50 to 100 lags. Given this evidence against the assumption of independent returns, it is important that models for financial assets be able to accommodate a dependence structure

Essays on modeling, hedging and pricing of insurance and financial products

Cette thèse est composée de trois articles abordant différentes problématiques en relation avec la modélisation, la couverture et la tarification des risques d’assurance et financiers. “A general class of distortion operators for pricing contingent claims with applications to CAT bonds” est un projet présentant une méthode générale pour dériver des opérateurs de distorsion compatibles avec la valorisation sans arbitrage. Ce travail offre également une nouvelle classe simple d’opérateurs de distorsion afin d’expliquer les primes observées dans le marché des obligations catastrophes. “Local hedging of variable annuities in the presence of basis risk” est un travail dans lequel une méthode de couverture des rentes variables en présence de risque de base est développée. La méthode de couverture proposée bénéficie d’une exposition plus élevée au risque de marché et d’une diversification temporelle du risque pour obtenir un rendement excédentaire et faciliter l’accumulation de capital. “Option pricing under regime-switching models : Novel approaches removing path-dependence” est un projet dans lequel diverses mesures neutres au risque sont construites pour les modèles à changement de régime de manière à générer des processus de prix d’option qui ne présentent pas de dépendance au chemin, en plus de satisfaire d’autres propriétés jugées intuitives et souhaitables.This thesis is composed of three papers addressing different issues in relation to the modeling, hedging and pricing of insurance and financial risks. “A general class of distortion operators for pricing contingent claims with applications to CAT bonds” is a project presenting a general method for deriving probability distortion operators consistent with arbitrage-free pricing. This work also offers a simple novel class of distortions operators for explaining catastrophe (CAT) bond spreads. “Local hedging of variable annuities in the presence of basis risk” is a work in which a method to hedge variable annuities in the presence of basis risk is developed. The proposed hedging scheme benefits from a higher exposure to equity risk and from time diversification of risk to earn excess return and facilitate the accumulation of capital. “Option pricing under regime-switching models: Novel approaches removing path-dependence” is a project in which various risk-neutral measures for hidden regime-switching models are constructed in such a way that they generate option price processes which do not exhibit path-dependence in addition to satisfy other properties deemed intuitive and desirable

Fuzzy Esscher changes of measure and copula invariance in Lévy markets

In the context of a multidimensional exponential Lévy market, we focus on the Esscher change of measure and suggest a more flexible tool allowing for a fuzzy version of the standard Esscher transform. Motivated both by the empirical incompatibility of market data and the analytical form of the standard Esscher transform (see [8]) and by the desire to introduce a pricing technique under incompleteness conditions, we detect the impact of fuzziness in terms of measure change function and in contingent claims' pricing. In a multidimensional setting the fuzzy Esscher transform is a copula whose invariance, under margins' transformations induced by a change of measure, is investigated and connected to the notion of the absence of arbitrage opportunities. We highlight how Esscher transform, primarily used in pricing techniques, preserves the invariance of the aggregation operator and it can be generalized to the fuzzy version assuming that the measurable functions defining the Choquet marginal integrals are increasing. Furthermore, the empirical evidence seems to suggest that a weaker concept of invariance may be more suitable, i.e. the ε-measure invariance, coherent with the Esscher fuzzy copula tool. An empirical experiment for our model will make clear how this blurring technique fits the market data

Near-optimal estimation of jump activity in semimartingales

In quantitative finance, we often model asset prices as semimartingales, with drift, diffusion and jump components. The jump activity index measures the strength of the jumps at high frequencies, and is of interest both in model selection and fitting, and in volatility estimation. In this paper, we give a novel estimate of the jump activity, together with corresponding confidence intervals. Our estimate improves upon previous work, achieving near-optimal rates of convergence, and good finite-sample performance in Monte-Carlo experiments.The author acknowledges the EPSRC for their support under grant EP/K000993/1.This is the final version of the article. It was first available from Institute of Mathematical Statistics via http://dx.doi.org/10.1214/15-AOS134

Efficient calculation of the Greeks

Monte Carlo Simulationen haben im Bereich des Finanzsektors in den letzten Jahren immer mehr an Bedeutung gewonnen. Diese Arbeit stellt eine neue Simulationsmethode vor um Preissensitivitäten von Optionen bezüglich eines bestimmten Verteilungsparameters, sogenannte “Greeks”, zu schätzen. Im Besonderen wird angenommen, dass der zugrundeliegende Prozess einem Lévy-Typ Prozess in diskreter Zeit entspricht. Unsere Methode basiert auf dem Ansatz der Maßwertigen Ableitung (MVD), welcher uns erlaubt die Ableitung als Differenz zweier Prozesse, sogenannten Phantomen, darzustellen. Wir diskutieren die Anwendbarkeit der Maßwertigen Ableitung für verschiedene Arten von Optionen in Kombination mit unterschiedlichen Modellen des zugrundeliegenden Prozesses. Des Weiteren liefern wir den Rahmen für die Verwendbarkeit der Maßwertigen Ableitung für pfadabhängige Optionen, wie zum Beispiel Lookback Optionen oder Asiatische Optionen.Monte Carlo simulation methods have become more and more important in the financial sector in the past years. In this work, we introduce a new simulation method for the estimation of the derivatives of prices of financial contracts w.r.t. certain distributional parameters, called the “Greeks”. In particular, we assume that the underlying financial process is a Lévy-type process in discrete time. Our method is based on the measure-valued differentiation (MVD) approach, which allows to represent derivatives as differences of two processes, called the phantoms. We discuss the applicability of MVD for different types of option payoffs in combination with different types of models of the underlying and provide a framework for the applicability of MVD for path-dependent payoff functions, as Lookback Options or Asian Options

Dynamic asset allocation using option implied distributions in an exponentially tempered stable Lévy market

Mestrado em Mathematical FinanceEste artigo explora o problema do portfólio ideal usando distribuições implícitas na opção quando o processo de preço subjacente é assumido como sendo conduzido por um processo exponencial de Levy. Em particular, a aplicação é levada a cabo usando um processo de difusão de salto Estável Exponencialmente Temperado como o componente martingale do preço das acções de log, e as preferências do investidor são assumidas sujeitas a uma função de utilidade CRRA. Densidades de um mês neutras ao risco são extraídas dos preços das opções usando um método de precificação por transformação e são subsequentemente transformadas na densidade ajustada ao risco ou no mundo real por meio de um modelo preservando a entropia mínima que mantém a parametrização do processo Levy. Um resultado de controle otimizado estocástico é então usado para construir um portfólio que consiste em um ativo de risco e sem risco, que é reequilibrado mensalmente. Descobriu-se que os portfólios formados usando as expectativas implícitas na opção sob a hipótese de mercado Levy, que são flexíveis o suficiente para capturar os momentos mais altos da distribuição implícita, são muito mais robustos aos riscos de cauda esquerda e oferecem melhorias estatisticamente significativas ao desempenho ajustado ao risco quando a aversão ao risco do investidor é baixa, porém isso diminui à medida que aumenta a aversão ao risco.This paper explores the optimal portfolio problem using option-implied distributions when the underlying price process is assumed to be driven by an exponential Levy process. In particular, the application is carried out using an Exponentially Tempered Stable jump-diffusion process as the martingale component of the log stock price, and the investor's preferences are assumed subject to a CRRA utility function. One month risk-neutral densities are extracted from option prices by using a transform pricing method and are subsequently transformed to the risk-adjusted, or real-world density via a model preserving minimal entropy transform which importantly maintains the parameterization of the Levy process. A stochastic optimal control result is then used to construct a portfolio consisting of a risky and risk-free asset which is rebalanced on a monthly basis. It is found that the portfolios formed using option-implied expectations under the Levy market assumption, which are flexible enough to capture the higher moments of the implied distribution, are far more robust to left-tail market risks and offer statistically significant improvements to risk-adjusted performance when investor risk aversion is low, however this diminishes as risk aversion increases.info:eu-repo/semantics/publishedVersio

The History of the Quantitative Methods in Finance Conference Series. 1992-2007

This report charts the history of the Quantitative Methods in Finance (QMF) conference from its beginning in 1993 to the 15th conference in 2007. It lists alphabetically the 1037 speakers who presented at all 15 conferences and the titles of their papers.

Fractional diffusion models and option pricing in jump models

Mestrado em Mathematical FinanceO problema de valorização de derivados tem sido o foco da investigação em Matemática Financeira desde a sua conceção. Mais recentemente, a literatura tem-se focado por exemplo em modelos que assumem que as dinâmicas do preço do ativo subjacente são governadas por um processo de Lévy (por vezes chamado um processo com saltos). Este tipo de modelo admite a possibilidade de eventos extremos (saltos), que não são devidamente capturados por modelos clássicos do tipo Black-Scholes, alicerçados no movimento Browniano. Foi também demonstrado ao longo da última década que se as dinâmicas do preço do ativo subjacente seguem certos processos de Lévy, tais como o CGMY , o FMLS e o KoBoL, os preços das opções satisfazem uma equação diferencial parcial fracionária. Nesta dissertação, iremos mostrar que se as dinâmicas do ativo subjacente seguem o denominado Processo Estável Temperado Generalizado, que admite como caso particular os suprareferidos processos CGMY e KoBoL, então os preços das opções satisfazem igualmente uma equação diferencial parcial fracionária. Além disso, iremos implementar um método simples de diferenças finitas para resolver numericamente a equação deduzida, e valorizar opções do tipo europeu.The problem of pricing financial derivatives has been the focal point of research within the field of Mathematical Finance since its conception. In recent years, one of the main areas of focus within the literature has been on models which assume that the dynamics of the price of the underlying asset are governed by a Lévy process (sometimes referred to as a jump process). This type of model admits the possibility of extreme events (jumps), which are not captured by classical Black-Scholes type models based on the Brownian motion. Over the last decades, the literature has further shown that if the dynamics of the price of the underlying is governed by certain Lévy processes, such as the CGMY , the FMLS and the KoBoL, the price processes of European-style options satisfy a variety of fractional partial differential equations (FPDEs). In this dissertation, we will show that if the underlying price dynamic follows a Generalized Tempered Stable process, which admits as particular cases the aforementioned CGMY and KoBoL processes, prices of options satisfy an FPDE of the same type. Further, we will implement a simple finite difference scheme to solve the FPDE numerically to price European-type options.info:eu-repo/semantics/publishedVersio