Risk Aversion, Intertemporal Substitution, and Option Pricing

This paper develops a general stochastic framework and an equilibrium asset pricing model that make clear how attitudes towards intertemporal substitution and risk matter for option pricing. In particular, we show under which statistical conditions option pricing formulas are not preference-free, in other words, when preferences are not hidden in the stock and bond prices as they are in the standard Black and Scholes (BS) or Hull and White (HW) pricing formulas. The dependence of option prices on preference parameters comes from several instantaneous causality effects such as the so-called leverage effect. We also emphasize that the most standard asset pricing models (CAPM for the stock and BS or HW preference-free option pricing) are valid under the same stochastic setting (typically the absence of leverage effect), regardless of preference parameter values. Even though we propose a general non-preference-free option pricing formula, we always keep in mind that the BS formula is dominant both as a theoretical reference model and as a tool for practitioners. Another contribution of the paper is to characterize why the BS formula is such a benchmark. We show that, as soon as we are ready to accept a basic property of option prices, namely their homogeneity of degree one with respect to the pair formed by the underlying stock price and the strike price, the necessary statistical hypotheses for homogeneity provide BS-shaped option prices in equilibrium. This BS-shaped option-pricing formula allows us to derive interesting characterizations of the volatility smile, that is, the pattern of BS implicit volatilities as a function of the option moneyness. First, the asymmetry of the smile is shown to be equivalent to a particular form of asymmetry of the equivalent martingale measure. Second, this asymmetry appears precisely when there is either a premium on an instantaneous interest rate risk or on a generalized leverage effect or both, in other words, whenever the option pricing formula is not preference-free. Therefore, the main conclusion of our analysis for practitioners should be that an asymmetric smile is indicative of the relevance of preference parameters to price options.

Return and Volatility performance comparison of Ethical and Non-ethical publicly-listed financial services companies

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Análisis de la relación entre el precio de la acción de Ecopetrol y los precios internacionales del petróleo

Este documento analiza mediante la metodología de cointegración de Johansen, la relación de largo plazo entre el precio de la acción de Ecopetrol en la Bolsa de Valores de Colombia y los precios del petróleo WTI y Brent. Los resultados del modelo indican que aunque no existe una relación de largo plazo entre cada uno de los precios de referencia y la acción, hay evidencia de una relación en el corto plazo entre el precio del crudo Brent y la acción, demostrada por una prueba de causalidad de Granger. Este resultado puede ser útil para el Gobierno y otros accionistas.

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Modelo telegráfico de valoración de opciones

En este trabajo construimos un modelo de mercado financiero basado en un proceso telegráfico más un proceso de saltos para la valoración de opciones Europeas. Vamos a asumir que el tamaño de los saltos es constante y después que es aleatorio, en ambos casos estos saltos ocurren cuando la tendencia del mercado cambia. Estos modelos capturan la dinámica del mercado en periodos con presencia de ciclos financieros. Mostraremos la estructura del conjunto de medidas neutrales al riesgo, además, de fórmulas explícitas para los precios de las opciones Europeas de venta y compra.

Option pricing in market models driven by telegraph processes with jumps

Esta tesis está dividida en dos partes: en la primera parte se presentan y estudian los procesos telegráficos, los procesos de Poisson con compensador telegráfico y los procesos telegráficos con saltos. El estudio presentado en esta primera parte incluye el cálculo de las distribuciones de cada proceso, las medias y varianzas, así como las funciones generadoras de momentos entre otras propiedades. Utilizando estas propiedades en la segunda parte se estudian los modelos de valoración de opciones basados en procesos telegráficos con saltos. En esta parte se da una descripción de cómo calcular las medidas neutrales al riesgo, se encuentra la condición de no arbitraje en este tipo de modelos y por último se calcula el precio de las opciones Europeas de compra y venta.

The information content of REIT credit rating actions and transparency

We examine the short-run and long-run price reaction of equity REIT shares following credit rating actions, testing the transparency of the REIT structure. Generally, the economic effect on the stock price is subdued for both upgrades and downgrades compared to prior literature examining the broader U.S. equity market. An examination of trading volume revealed a significant increase in trading in reaction to downgrade credit rating changes, with a more subdued response to upgrades. The findings support the notion that REITs are more publicly forthcoming about the expectation of positive news in comparison to negative news.

Does managerial turnover affect football club share prices?

This paper analyses the 53 managerial sackings and resignations from 16 stock exchange listed English football clubs during the nine seasons between 2000/01 and 2008/09. The results demonstrate that, on average, a managerial sacking results in a post-announcement day market-adjusted share price rise of 0.3%, whilst a resignation leads to a drop in share price of 1% that continues for a trading month thereafter, cumulating in a negative abnormal return of over 8% from a trading day before the event. These findings are intuitive, and suggest that sacking a poorly performing manager may be welcomed by the markets as a possible route to better future match performance, while losing a capable manager through resignation, who typically progresses to a superior job, will result in a drop in a club’s share price. The paper also reveals that while the impact of managerial departures on stock price volatilities is less clear-cut, speculation in the newspapers is rife in the build-up to such an event.

Number preference in Australian stocks

Stock price rallies/declines often terminate at price levels that are interpreted by many as areas of psychological resistance or support, while an alternative interpretation is that they coincide with price clusters. Some of these price levels tend to repeat with a regularity that is inconsistent with mere chance. In this paper, the existence of price clusters and psychological barriers is tested on a sample of 20 Australian stocks. We consider two number sequences, both derived from a base number of 100, as well as integer price levels. It is shown that Australian stock price data are not uniformly distributed and that for the majority of the stocks, price swing highs and lows are associated with certain recurring price levels. Some of the implications for trading and investing are considered.

Is jump risk in iTraxx Sector Indices diversifiable?

The article presents an analysis of jump risks in iTraxx Europe index in a multivariate structural time-series setting for the stochastic process, as well as in the credit default swap (CDS) market. It also examines the rapid development of the credit derivatives market, particularly the CDS market. This analysis found a significant Poisson-distributed jumps in the iTraxx Non-Financials index and its subindices. Based on a statistical analysis, nondiversifiable jump risk strongly exists in the CDS market.

Corporate political connections and the 2008 Malaysian election

We examine whether the relationship between political connections and firm value is moderated by the length of time firms have been politically connected. We find that compared to firms with political connections for a short period, firms with political connections for a long period have a smaller magnitude of negative stock price reaction to the 2008 General Election loss of the supermajority by the ruling party in Malaysia. We also find that the smaller magnitude of negative stock price reaction is, in part, attributable to improvements in board of director characteristics. Furthermore, we find that while the performance subsequent to the General Election of politically connected firms is worse than that of non-politically connected firms, firms with political connections for a long period exhibit better performance than those connected for short periods. Collectively, the evidence shows that the length of political connections is an important factor that moderates economic value.

Gender-diverse boards and properties of analyst earnings forecasts

Using a sample of 2,200 U.S. listed firm-year observations (2001-2007), this study shows a positive (negative) relation between gender diversity on corporate boards and analysts' earnings forecast accuracy (dispersion), after controlling for earnings quality, corporate governance, audit quality, stock price informativeness, and potential endogeneity. Our findings are important as they suggest that board diversity adds to the transparency and accuracy of financial reports such that earnings expectations are likely to be more accurate for these firms.

A GARCH model for testing market efficiency

In this paper we propose a generalised autoregressive conditional heteroskedasticity (GARCH) model-based test for a unit root. The model allows for two endogenous structural breaks. We test for unit roots in 156 US stocks listed on the NYSE over the period 1980 to 2007. We find that the unit root null hypothesis is rejected in 40% of the stocks, and only in four out of the nine sectors the null is rejected for over 50% of stocks. We conclude with an economic significance analysis, showing that mostly stocks with mean reverting prices tend to outperform stocks with non-stationary prices.

“Ombro-cabeça-ombro”: testando a lucratividade do padrão gráfico de análise técnica no mercado de ações brasileiro

A partir de uma adaptação da metodologia de Osler e Chang (1995), este trabalho avalia, empiricamente, a lucratividade de estratégias de investimento baseadas na identificação do padrão gráfico de Análise Técnica Ombro-Cabeça-Ombro no mercado de ações brasileiro. Para isso, foram definidas diversas estratégias de investimento condicionais à identificação de padrões Ombro-Cabeça- Ombro (em suas formas padrão e invertida), por um algoritmo computadorizado, em séries diárias de preços de 47 ações no período de janeiro de 1994 a agosto de 2006. Para testar o poder de previsão de cada estratégia, foram construídos intervalos de confiança, a partir da técnica Bootstrap de inferência amostral, consistentes com a hipótese nula de que, baseado apenas em dados históricos, não é possível criar estratégias com retornos positivos. Mais especificamente, os retornos médios obtidos por cada estratégia nas séries de preços das ações, foram comparados àqueles obtidos pelas mesmas estratégias aplicadas a 1.000 séries de preços artificiais - para cada ação - geradas segundo dois modelos de preços de ações largamente utilizados: Random Walk e E-GARCH. De forma geral, os resultados encontrados mostram que é possível criar estratégias condicionais à realização dos padrões Ombro- Cabeça-Ombro com retornos positivos, indicando que esses padrões conseguem capturar nas séries históricas de preços de ações sinais a respeito da sua movimentação futura de preços, que não são explicados nem por um Random Walk e nem por um E-GARCH. No entanto, se levados em consideração os efeitos das taxas e dos custos de transação, dependendo das suas magnitudes, essas conclusões somente se mantêm para o padrão na sua forma invertida