We live in an era where internationalization and globalization are two extremely attractive concepts. People aim to create a society where limits and restrictions are erased and a thriving society is a reality. Numerous transformations have occurred in order to realize this and one of the most vital ones is the globalization of the economy. The globalization was made possible through the discovery on the capital market. This market enables people to trade with each other, no matter place or time. Thus, a more efficient solution is offered for rapid and significant transfers such as loans and investment. According to various researchers, the capital market determines, in a way, which company will grow and which will stagnate in development. However, the capital market needs to be efficient in order to offer the services intended. The aim of this dissertation is to explain how efficient the capital market is when incorporating information regarding football player transfers. By examining the empirical findings, it will also be able to establish if assets of the same market value cause different share price fluctuations depending on if they are acquired or sold.

A cointegration analysis on a triangle of high frequency exchange rates is presented. Market efficiency requires the triangle to be cointegrated and the cointegration term to be a martingale difference sequence. We find empirical evidence against market efficiency for very short time horizons: The cointegration term does not behave like a martingale difference sequence. In an out-of-sample forecasting study the cointegrated vector autoregressive (VAR) model is found to be superior to the naive martingale. Finally, a simple trading strategy shows that the VAR also has a significant forecast value in economic terms even after accounting for transaction costs. (author's abstract) / Series: Working Papers SFB "Adaptive Information Systems and Modelling in Economics and Management Science"

Bitcoins have the potential to fundamentally change the way value is transferred globally. Their rapid adoption over the past four years has led many to consider the possible results of such a technology. To be a viable currency, however, it is imperative that the market for trading Bitcoins is efficient. By examining the changes in availability of predictable outsized returns and market liquidity over time, this paper examines historical Bitcoin market efficiency and establishes correlations between market liquidity, price predictability, and return data. The results provide insight into the turbulent nature of Bitcoin market efficiency over the past years, but cannot definitively measure the magnitude of the change due to the limitations in efficiency analysis. The most meaningful result of this study, however, is the statistically significant short-horizon price predictability that existed over the duration of the study, which has implications for Bitcoin market efficiency as well as for continued research in short-horizon Bitcoin price forecasting models.

在本篇研究中，我們考慮了未預料到的訊息進而檢定歐元兌美元外匯市場的效率性。並且，我們將資料分為金融海嘯發生前後兩段期間，資料頻率為日資料。有別於之前文獻使用的訊息不完整且可能不為真實的訊息，我們考慮了所有美國及歐盟定期公布的相關經濟數據與指標，並定義未預料到訊息為數據真實質與預期值之間的差距。我們的實證結果指出，在金融海嘯前，是接受市場效率性假說的，雖然此一結果在金融海嘯發生後並不成立，但未預料到訊息的衝擊，確實會影響外匯市場效率性檢定的結果。因此過去文獻無法支持市場效率性假說之原因可能源自於忽略了未預料訊息的考量。另外，我們也發現，美國訊息與歐盟訊息存在不對稱的影響力，且市場傾向於忽略歐盟區的數據。 / In this paper, we examine the hypothesis of market efficiency in euro/dollar with un-anticipated news, which are defined as the difference between actual values and the market’s forecasts. The research data are divided into two periods of time, before and after the beginning of financial crisis. Unlike previous literatures in which the un-anticipated news are incomplete and may be unreal, our paper adopted all macroeconomic announcements and indicators of United States and the European Union. Our results before the financial crisis indicate that the market efficiency hypothesis is accepted, although the result fails to hold after the financial crisis. The result still shows the importance of the un-anticipated news in testing the foreign exchange market efficiency hypothesis. Therefore the rejection of efficiency hypothesis on foreign exchange market in the literature may result from the lack of un-anticipated news in the model. In addition, we found that impacts of U.S. and EU un-anticipated news are asymmetric on the exchange rate. Besides, the market participants tend to ignore the EU news during both periods of time.

財務報表在資本市場扮演何種角色是會計學者長久以來關注的焦點。Ohlson的研究將實證研究的重心從解釋股價的行為轉向至會計資訊與企業價值關聯的研究。本研究以美國市場為背景，加入分析師對盈餘預測因素，測試剩餘淨利模型實證上的有效性，並且用以檢視是否能以此模型建立超越大盤的投資組合。實證結果顯示發現分析師的盈餘預測作為其他資訊之代理變數以及分析師之長期成長預測捕捉企業未來成長潛質，有助於提升模型對股價的解釋能力。本研究認為成長機會對股價具有正向之影響，現時股價表現反映投資人對未來預期的結果。

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.

Este trabalho tem por objetivo verificar se há diferença quanto ao nível de significância estatística no cálculo do retorno anormal realizado através de quatro modelos estatísticos utilizados em estudos de eventos, tendo como objeto de estudo empresas no mercado de ações no Brasil durante o período de março de 2003 até julho de 2010 na Bovespa. Considerando a importância do cálculo do retorno anormal nos estudos de eventos, bem como possíveis variações de resultados decorrentes da escolha do modelo de cálculo, este estudo utiliza um tema bastante conhecido, qual seja, o anúncio de recompra de ações feito pela própria companhia emissora dos títulos. A metodologia utilizada nesta pesquisa foi quantitativa, utilizando o estudo de corte transversal. Os resultados apontam que há diferença entre os níveis de significância encontrados. Ao analisar o gráfico dos modelos calculados no período da janela do evento, verificou-se que as empresas que recompraram ações a fizeram quando os papéis estavam com retorno anormal acumulado negativo e, após a recompra, os papéis tiveram retornos anormais acumulados positivos. Recalculou-se os dois modelos que utilizam o Ibovespa em sua fórmula de cálculo, através de um Ibovespa sem ponderação e conclui-se que os resultados apontam na direção de se evitar o uso de índices ponderados de mercado, preferindo a utilização de carteiras compostas apenas com uma ação para cada empresa componente da carteira de controle. Após este recálculo, verificou-se que o modelo que era menos próximo dos demais graficamente era o modelo de retorno ajustado ao mercado ponderado. Por fim, as evidências empíricas indicam que o mercado de capitais brasileiro ajusta tempestivamente os papéis das empresas que realizaram recompra de ações, em linha com o que prescreve a hipótese do mercado eficiente na sua forma semiforte. / The objetive of this study is to verify if there is any difference regarding the statistical significance level on the abnormal return calculation done through four statistical models used in event studies, having as the study object companies negotiated on the Bovespa Stock Exchange from March 2003 to July 2010. Considering the abnormal return calculation relevance in event studies, as well as the possible variations of results due to the calculation model of choice, this study uses an overly known theme, the stock repurchase announcement done by the own company. The methodology used in this research was quantitative, using the transversal cut study. The results demonstrated that there is difference among the significance levels found. When analyzing the graphs of the calculated models on the event window period, it was verified that the companies that repurchased the stocks done so when their shares were with abnormal accumulated negative returns and, after repurchasing, the shares had abnormal accumulated positive returns. The two models that uses the Ibovespa in its calculation formulae were recalculated, through an non-weighted Ibovespa and the conclusion pointed by the results is that the use of weighted market indexes must be avoided, giving preference to the use of portfolios composed by one share for each company that is comprised in the control portfolio. After this recalculation, it was verified that the models using the weighted market return models were graphically distant from all the other models. Lastly, the empirical evidences have demonstrated that the Brazilian capital market adjusts in a timely manner the shares of the companies that undergone the repurchase of their stocks, in line with what is expected by the efficient market hypothesis on its semi-strong form.

Através de estudo de evento este trabalho analisa o impacto provocado pelo anúncio de recompra de ações sobre os seus próprios preços, utilizando como referência, as empresas que anunciaram aquisição de ações de sua emissão, através de publicação de fato relevante na Comissão de Valores Mobiliário (CVM), nos exercícios de 2003 a 2009. O estudo pressupõe eficiência de mercado na sua forma semi-forte e identifica retorno anormal, estatisticamente significativo na data um do evento, ou seja, um dia após o anúncio. Os retornos acumulados de três dias são regredidos contra dados da recompra e os resultados reforçam a hipótese de sinalização, já sugerida pela análise do gráfico do retorno anormal acumulado, com os retornos indicando alta decorrente de pressão de preços. Os modelos de regressão utilizados, incluindo variáveis contábeis associadas a outras hipóteses explicativas, não encontram resultados significativos que dêem suporte a outras possíveis motivações propostas na literatura acadêmica. / Through event study this study examines the impact caused by the announcement of share repurchases on its own prices, using as reference, the companies announced the acquisition of shares issued through the publication of material fact in the Securities Exchanges Commission (CVM) in the years 2003 to 2009. The study assumes market efficiency in its semi-strong and identifies abnormal return is statistically significant at the time of an event, one day after the announcement. The cumulative returns for three days are regressed against the repurchase data and findings support the signaling hypothesis, already suggested by the analysis of the graph of cumulative abnormal return, with returns showing high due to price pressure. The regression models used, including accounting variables associated with other hypothes s, there are significant results that support other possible motives proposed in academic literature.

This diploma thesis analyses the market efficiency hypothesis of chosen currency pairs EUR/USD, EUR/CZK and USD/CZK. The aim of this study is to describe the price behaviour of chosen financial assets and verify the random walk hypothesis on the foreign exchange market. Model of random walk says there is no relationship between historical and future prices, so price changes are random and cannot be predicted. Random walk hypothesis was tested by chosen statistic tests runs test, test of auto-correlation, variance ratio test and unit root test (Augmented Dickey-Fuller Test). Data were collected through the online trading platform and tested in EViews. Period of testing for daily changes (D1) was chosen from 31.12.2009 to 29.12.2017 and for weekly changes (T1) from 2.1.2005 to 29.12.2017. This thesis proved weak-form efficiency of EUR/USD and USD/CZK for both daily changes and weekly changes in a chosen period. Inefficient behaviour of daily changes of EUR/CZK (D1) was indicated by runs test, test of autocorrelation and variance ratio test. There is a question what the cause of inefficiency is. The most likely explanation is currency intervention of the Czech National Bank which took place from April 2013 to April 2017 in order to achieve the inflation target and prevent deflation. Traders could also achieve profits by speculating on appreciation of Czech Crown below 27,-crowns/euro which is not in harmony with efficient-market hypothesis. Moreover, currency pair EUR/CZK is not liquid as major currency pairs and there are bigger transaction costs because of bid-offer spread. This work can contribute to next research in connection with results of this study. To verify if the cause of inefficient behaviour of daily price changes of EUR/USD are currency interventions of the Czech National Bank, I would suggest testing efficient-market hypothesis exactly at the time of interventions. It would be also suitable to compare results of different methodologies including testing in short-time intervals of price changes.