O propósito dessa pesquisa é estudar a relação entre a revelação de informação corporativa e o comportamento de uma seleção de empresas com fortes políticas de revelação de informação e alto grau de capitalização do Mercado Acionário da Colômbia, para o ano 2014. Mediante esse estudo, é analisada a microestrutura utilizando informação de alta frequência e notícias corporativas publicadas na plataforma de Bloomberg Professional Services. A metodologia de análise para prover evidência da relação foi o estudo de eventos, testando a significância da diferença entre as médias e medianas pré-evento e pós-evento de alguns indicadores de liquidez, retorno e volatilidade. Os resultados permitem concluir que a disseminação de informação tem um impacto sobre a liquidez e a volatilidade do mercado. Percebe-se que no período posterior à publicação das notícias, o tamanho dos bid-ask spreads e a volatilidade do midquote diminui, os investidores negociam em média menores volumes e quantidade de operações e submetem menor quantidade de intenções de compra e venda. / The purpose of this investigation is to study the relationship between corporate disclosure and the behavior of a selection of companies, with strong disclosure policies and high market capitalization ratio of the Colombian Stock Market, for the entire year 2014. The idea of this investigation is to analyze the market microstructure using high frequency data and corporate information publicized through the Bloomberg professional services platform. The estimation technique to provide evidence of the relationship is the event study, testing the significance of the difference between the pre-event and post-event average and median of some indicators of return, liquidity and volatility. The results prove that the disemintation of information impact the market liquidity and volatility. It is noticed that in the post-event window, bid-ask spreads and volatility of the midquote decreases, traders negociate on average lower volums and number of transactions and submit fewer buy and sell order intentions.

O propósito dessa pesquisa é estudar a relação entre a revelação de informação corporativa e o comportamento de uma seleção de empresas com fortes políticas de revelação de informação e alto grau de capitalização do Mercado Acionário da Colômbia, para o ano 2014. Mediante esse estudo, é analisada a microestrutura utilizando informação de alta frequência e notícias corporativas publicadas na plataforma de Bloomberg Professional Services. A metodologia de análise para prover evidência da relação foi o estudo de eventos, testando a significância da diferença entre as médias e medianas pré-evento e pós-evento de alguns indicadores de liquidez, retorno e volatilidade. Os resultados permitem concluir que a disseminação de informação tem um impacto sobre a liquidez e a volatilidade do mercado. Percebe-se que no período posterior à publicação das notícias, o tamanho dos bid-ask spreads e a volatilidade do midquote diminui, os investidores negociam em média menores volumes e quantidade de operações e submetem menor quantidade de intenções de compra e venda. / The purpose of this investigation is to study the relationship between corporate disclosure and the behavior of a selection of companies, with strong disclosure policies and high market capitalization ratio of the Colombian Stock Market, for the entire year 2014. The idea of this investigation is to analyze the market microstructure using high frequency data and corporate information publicized through the Bloomberg professional services platform. The estimation technique to provide evidence of the relationship is the event study, testing the significance of the difference between the pre-event and post-event average and median of some indicators of return, liquidity and volatility. The results prove that the disemintation of information impact the market liquidity and volatility. It is noticed that in the post-event window, bid-ask spreads and volatility of the midquote decreases, traders negociate on average lower volums and number of transactions and submit fewer buy and sell order intentions.

O propósito dessa pesquisa é estudar a relação entre a revelação de informação corporativa e o comportamento de uma seleção de empresas com fortes políticas de revelação de informação e alto grau de capitalização do Mercado Acionário da Colômbia, para o ano 2014. Mediante esse estudo, é analisada a microestrutura utilizando informação de alta frequência e notícias corporativas publicadas na plataforma de Bloomberg Professional Services. A metodologia de análise para prover evidência da relação foi o estudo de eventos, testando a significância da diferença entre as médias e medianas pré-evento e pós-evento de alguns indicadores de liquidez, retorno e volatilidade. Os resultados permitem concluir que a disseminação de informação tem um impacto sobre a liquidez e a volatilidade do mercado. Percebe-se que no período posterior à publicação das notícias, o tamanho dos bid-ask spreads e a volatilidade do midquote diminui, os investidores negociam em média menores volumes e quantidade de operações e submetem menor quantidade de intenções de compra e venda. / The purpose of this investigation is to study the relationship between corporate disclosure and the behavior of a selection of companies, with strong disclosure policies and high market capitalization ratio of the Colombian Stock Market, for the entire year 2014. The idea of this investigation is to analyze the market microstructure using high frequency data and corporate information publicized through the Bloomberg professional services platform. The estimation technique to provide evidence of the relationship is the event study, testing the significance of the difference between the pre-event and post-event average and median of some indicators of return, liquidity and volatility. The results prove that the disemintation of information impact the market liquidity and volatility. It is noticed that in the post-event window, bid-ask spreads and volatility of the midquote decreases, traders negociate on average lower volums and number of transactions and submit fewer buy and sell order intentions.

Most of the prior research in the area of monthly regularities has been based on the Gregorian calendar; by contrast, little attention has been given to other calendars based on different religions or cultures. This thesis examines monthly calendar anomalies in the Pakistani stock market for both the Gregorian calendar and its Islamic counterpart. This is one of the first studies to investigate both calendars for monthly seasonality in one investigation on the same dataset. Empirical studies of the Pakistani stock market that have examined monthly calendar anomalies are relatively sparse when compared with investigations from other emerging markets throughout the world. Even the findings from the small number of Pakistani investigations that have examined for the presence of monthly calendar anomalies have arrived at different conclusions about the predictability of equity returns at different times within a year. Since the conclusions of these findings have been mixed, the current study undertakes further work on this topic to offer some clarity in this area; this thesis arrives at a firm conclusion about the monthly calendar anomaly. For the purpose of this thesis, both qualitative and quantitative research methods were employed. Firstly, 19 face-to-face interviews were conducted with brokers, regulators and individual investors to ascertain their views about share price regularities with regards to monthly calendar anomalies and to gain some insights about the role of investor sentiment in the Pakistani stock markets. Secondly, share returns for a sample of 106 companies listed on the KSE over the 17 year period from 1995 to 2011 were analysed to determine whether Pakistani stock markets are weak-form efficient or whether security price changes can be predicted from knowledge of the month when the return is earned; it also investigates whether there is a change in the risk (volatility) of shares in different months which might explain any pattern in returns. To answer these questions various research methods were employed. The results of the interviews suggest that most respondents believed that share prices exhibit patterns in certain months of the year. The most common pattern highlighted by the interviewees related to the month of January for the Gregorian calendar and Ramadan for the Islamic calendar. Interviewees also argued that volatility declined during the religious month of Ramadan; they attributed these changes to investor sentiment and religious duties. Overall, the results suggested that monthly calendar anomalies may be present in the market and that these are studied by investors in an attempt to earn profit. The results from the quantitative analyses supported the findings from the interviews. Initial analyses suggested that returns varied significantly during certain months which indicate that the market might not be efficient. Further, investigations for seasonality in both the mean and volatility of returns offered conflicting evidence; very little statistical evidence of monthly seasonal anomalies was identified in average returns. However, monthly patterns were present in the variance of equity price changes in Pakistan. Overall, the results confirm that whatever monthly seasonality may be present in the equity prices of Pakistani companies, it is more pronounced in the volatility data than in the mean return numbers. These findings may have useful implications for trading strategies and investment decisions; investors may look to gain from managing the risk of their portfolios due to time varying volatility documented in the findings of this thesis. Further, the results of this thesis have interesting implications for our understanding of the dynamics of equity volatility in the Pakistani stock market.

This dissertation is concerned with the relationship between accounting earnings and stock prices. It consists of three empirical papers, all using a sample of firms listed on the Stockholm Stock Exchange (1990-2008). The first paper documents the existence of a drift in stock prices subsequent to quarterly earnings announcements. Two interesting empirical observations are that the drift is only significant for longer holding periods and that the drift on the short position, i.e. after bad earnings news, is negligible. The lack of downward drift on the short position is interpreted as an indication of the post-earnings announcement drift, at least partly, being explained by investors demanding a compensation for a risk factor that is omitted in the test design. The second paper illustrates under what conditions information risk in the earnings signal might explain a low announcement reaction and a price drift in the post-announcement period. It is hypothesized that two earnings signals – based either on GAAP earnings or core earnings – have different levels of information uncertainty with respect to how they depict the value creation of the firm. In the empirical sections, it is concluded that the low immediate announcement reaction and high post-announcement drift for the GAAP earnings signal is due to this signal being perceived by investors as containing more uncertainty than the core earnings signal. It is argued that this uncertainty might be due to GAAP earnings encompassing items that prior research has shown more likely to be manipulated and/or to contain estimation error. The positive association between information risk and expected return is further investigated in the third paper, where information risk is measured by earnings quality metrics. Using a new approach to estimate the implied cost of capital, it is found that Swedish investors demand a higher expected return for firms with poor earnings quality, i.e. firms associated with higher information risk. / Diss. Stockholm : Handelshögskolan i Stockholm, 2011