Stock market prediction has been a hot topic lately due to advances in computer technology and economics. One economic theory, called Efficient Market Hypothesis (EMH), states that all known information is already factored into the prices which makes it impossible to predict the stock market. Despite the EMH, many researchers have been successful in predicting the stock market using neural networks on historical data. This thesis investigates stock prediction using both linear regression and neural networks (NN), with a twist. The inputs to the proposed methods are a number of profit predictions calculated with stochastic methods such as generalized autoregressive conditional heteroskedasticity (GARCH) and autoregressive integrated moving average (ARIMA). By contrast the traditional approach was instead to use raw data as inputs. The proposed methods show superior result in yielding profit: at best 1.1% in the Swedish market and 4.6% in the American market. The neural network yielded more profit than the linear regression model, which is reasonable given its ability to find nonlinear patterns. The historical data was used with different window sizes. This gives a good understanding of the window size impact on the prediction performance.

金融商品的價值是否可以預測呢？由避險基金的操作績效以及華爾街著名分析師的事前看法和事後印證來看，答案幾乎是肯定的。不過，大多數的投資人卻依然無法獲利。站在學術的角度上來看，[Fama ,1970]的效率市場假說告訴我們，一個有效率的市場是無法獲得超額報酬的，這論點也經常被學者用來檢驗市場是否具有效率性，研究的結果也都是證明市場是無效率的。因此，我們希望藉由發展專家對於股價指數的漲跌推論規則之本體論來提升金融商品領域之知識管理的廣度與深度。 本體論(Ontology)是知識管理的表現方式之一，[Gruber ,1993]闡述本體論是一種詞彙的規格，用來呈現我們想要分享的領域；可以定義類別、關係、功能、與其他物件。由於本體論提供的是一個領域嚴謹豐富的理論因此相當適合使用在知識工程的領域上[劉紅閣、鄭麗萍與張少方 ,2005]。另外，本體論的建構過程和物件導向設計非常的類似[Chandrasekaran, Josephson & Benjamins ,1999]，因此，在研究的過程中，我們將以物件導向設計來輔助本體論的分析。最後，使用Protégé 3.0這套相當普及化的本體論編輯工具作為系統實做的工具。 / Is the value of Financial banking products predicable? In view of the operating performance of hedge fund and the preliminary insights and the evidences afterward from the well-known analyst of Wall Street, the answer is almost positive. Nevertheless, the majority of investors still can not make profits from it. Based on the Academic points, (Fama, 1970) the theory of hypothesis if efficient market showed us that we can not make extra profits from the efficient market. And it is often used to examine whether the market is of efficiency. And the result of research also proved that the market is inefficient. Therefore, it is desired that we enhance the width and deepness of knowledge management of financial banking products with the Ontology of the inferred up-and-down principal of stock index developed by the efforts of experts. Ontology is one of the ways presenting knowledge management. (Gruber, 1993) explains that the ontology is the specifications of terminology which presents the domains we would like to share with. Classes, Relations, functions and other objects could be defined by that. Ontology provide us with the theory of strictness and richness of domains, therefore, it is very suitably utilized in the domains of knowledge engineering[劉紅閣、鄭麗萍與張少方 ,2005]. Besides, the construction process of Ontology is very similar to the object-oriented design. [Chandrasekaran, Josephson & Benjamins ,1999] Based on this, we will use the object-oriented design to assist the analysis of Ontology through our research . At last, Protégé 3.0 which is the very popular editing tool of Ontology is used as a tool for the system implementation.

Made available in DSpace on 2016-04-25T16:45:04Z (GMT). No. of bitstreams: 1 Tiago Alves Costa.pdf: 830440 bytes, checksum: 40b830a47bb712666dd4a4ecfbcde61c (MD5) Previous issue date: 2008-04-29 / The finance science, as all sciences, shows an evolutionary line and according to Kuhn (1970), it is marked by shortly periods of knowledge accumulation. However, according to the author, such periods are inserted with scientific revolutions. In other words, the scientific evolution is stamped by revolutions which abandon oldfashioned paradigm and create new ones. The revolution is followed by a period where the researches are guided by the new paradigm and its purpose is strengthen the own paradigm. In other way, the finance science has today a central paradigm well-known by efficiency market hyperlink (EMH) which was witnessed and adopted by the entire scientific community around the 70 s. And since those times, almost entire research done in finance, mainly until the de 90 s, was leaded and done to validate the EMH. This dissertation attempted to evidence that the finance evolutionary line proposed by Haugen (2000) follows the same principle evidenced by Kuhn (1970), and in the present-day, the EMH find itself in a period which precede the scientific revolution which is called by time crisis by Kuhn (1970). This time crisis could weaken the EMH and open a space to create a new paradigm. This way, the proposal of dissertation is to prove how the revolutionary process will happen in finance too, soon after, to prove what would the candidates more inclined to replace the EMH be as a central paradigm in finance. To do so, this work considered only two candidates: the behavioral finance and the chaos theory. To do this analyze it was used the schooling principles nominated by Mckinley, Mone and Moon (2002). Such authors propose that a thought must display a combination of novelty, continuity, and scope to achieve school status in organizational theory. The purpose of this dissertation is to do a theory ransom which intends to show the fragility of the EMH as a central paradigm that orients the finance researches. The dissertation concludes that the current finance faces a crisis, and in this period, the behavioral finance displays the biggest chance to replace the EMH in the near future, however, the chaos theory provides the bigger promise considering a far future / A ciência das finanças, como toda ciência, apresenta uma linha evolutiva que de acordo com Kuhn (1970) é marcada por períodos de breve acumulação de conhecimento. Porém, de acordo com o autor, tais períodos são intercalados com revoluções científicas. Em outras palavras, a evolução científica é marcada por revoluções que abandonam antigos paradigmas e criam novos. Posteriormente à revolução, segue se um período onde as pesquisas são guiadas pelo novo paradigma com o propósito de fortalecer o próprio paradigma. De outra forma, a ciência financeira possui hoje um paradigma central conhecido como a hipótese de mercados eficientes (HME) que foi reconhecida e adotada pela comunidade científica por volta da década de 70. E desde aquela época, quase toda pesquisa feita na área, principalmente até a década de 90, foi guiada, e feita para validar e fortalecer a própria HME. Nesse sentido, este trabalho procurou evidenciar que a linha evolucionária das finanças proposta por Haugen (2000) segue o mesmo princípio evidenciado por Kuhn (1970), e que no momento atual, a HME encontra-se em um período que antecede a revolução científica e que é chamado de período de crise por Kuhn (1970). Esse período de crise, que antecede as revoluções, poderia enfraquecer a HME e abrir espaço para a criação de um novo paradigma. Sendo assim, o trabalho também propõe a evidenciar como que o processo de revolução poderá acontecer em finanças, e em seguida, também propõe quais seriam os candidatos mais propensos a substituir a HME como paradigma central em finanças. Para tanto, o trabalho considerou apenas dois candidatos: as finanças comportamentais e a teoria do caos. Para fazer tal análise, foram utilizados os princípios de escolarização propostos por Mckinley, Mone e Moon (2002). Tais autores propõem que um pensamento tem que possuir três características (novidade, continuidade e escopo) para ser considerado uma escola em teoria organizacional. O propósito do trabalho é de um resgate teórico básico que procura evidenciar a fragilidade da HME enquanto paradigma principal norteador das pesquisas em finanças. Assim sendo, o trabalho conclui que as finanças atuais enfrentam uma crise, e que nesse período, as finanças comportamentais apresentam a maior chance de substituir a HME em um futuro próximo, porém, a teoria do caos fornece uma promessa maior considerando um futuro mais distante

The aim of this paper is to test whether an investment strategy originally created by Piotroski (2000), can be refined by combining it with the price-to-earnings-anomaly. In detail, we accomplish this by implementing Piotroskis F_SCORE-model to identify and consequently separate financially weak- and strong firms. Furthermore, we create an investment portfolio based on a combination of the highest rated companies according to the F_SCORE-model, and the most undervalued companies from the price-to-earnings-anomaly, to create a joint investment strategy (M_STRAT). This is carried out during the time-period 1999-2009, while reconstructing the portfolio annually. The results of our study show that, by combining the two models, we are able to achieve a market-adjusted return of 44,1%, hence amplifying the original F_SCORE-model by 17%.

One could argue that the most discussed topic in finance is whether or not it is possible to “beat the market”. Even though many people claim to do this, there is little evidence to support the idea that one can consistently beat the market over a long period of time. There are indeed several examples of investors who have managed to outperform the market consistently for a long time, but the efforts of these individuals or institutions could by many be considered to be pure luck. One of the many strategies that have been evaluated by several researchers and is said to generate a risk adjusted return greater than that of the market, is one based on the P/E-effect. This strategy is based on the financial ratio P/E – price divided by earnings – and used by constructing portfolios consisting of stocks with low P/E ratios. Several studies have confirmed the existence of the P/E-effect on various stock markets around the world and over different time periods. On the Swedish market, however, few studies have generated the same results. Most of these studies can be considered to be insufficient with regards to sample sizes and methods, spawning a need for more extensive studies. We have examined the P/E strategy on the Swedish Stock Exchange (SSE) between 2004 and 2012. The sample included 358 companies (excluding financial companies) with available necessary data. The stocks were divided into five portfolios based on their yearly P/E ratios (low to high), upon which the monthly returns of the individual stocks were calculated using a logarithmic formula. The returns were also risk adjusted using the Capital Asset Pricing Model (CAPM), followed by a regression analysis to see if possible abnormal returns could be considered to be statistically significant for the examined time period. The results of our study indicate that the P/E effect is not present on the Swedish Stock Exchange during the examined time period, and we therefore conclude that it was not possible to utilize a strategy based on the P/E effect between 2004 and 2012 in order to achieve an abnormal return. The results can be used to argue that the Swedish stock market is more efficient than for example the U.S. stock market where the P/E effect has been found to exist.

The purpose of this study is to investigate the effects of COVID-19 initial hit and the associated lockdowns effect on the semiconductor industry. The study emanates from factors of return on investment in the equity market using the CAPM model alongside the theories of EMH and behavioral finance. The semiconductor industry is represented by the SOX index, and the S&P 500 index representing the general markets. The mapping of movements in these indexes are done in a daily time series between 01/01/2018 to 29/11/2021 to find out the behavior of the market during a period of shock. The conclusion is that equity markets is affected by lockdowns, but also has other factors affecting the industry. / Syftet med denna studie är att undersöka effekterna av COVID-19 och karantänregleringar på halvledarindustrin. Studien utgår från faktorer som risk och avkastning på aktiemarknaden genom att använda CAPM-modellen tillsammans med teorierna EMH och beteendeekonomi. Skiftet på aktiemarknaden observeras genom risk och avkastning på SOX-indexet som representerar halvledarindustrin och S&P 500-indexet som representerar de allmänna marknaderna. Kartläggningen av rörelser i dessa index görs i en daglig tidsserie mellan 01/01/2018 och 29/11/2021 för att ta reda på om det är värt att investera i halvledarindustrin under pandemin. Slutsatsen är att aktiemarknaderna kan överreagera på nyheter och att halvledarmarknaden initialt är motståndskraftig mot covid-19. Marknadensmotståndskraft följs dock av längre prissvängningar som resulterar i högre avkastning och lägre risk vilket gör investeringar i halvledarindustrin betydligt bättre än S&P 500.

The study investigates whether the main capital market theories and pricing models provide a reasonably accurate description of the working and efficiency of capital markets, of the pricing of shares and options and the effect the risk/return relationship has on investor behaviour. The capital market theories and pricing models included in the study are Portfolio Theory, the Efficient Market Hypothesis (EMH), the Capital Asset Pricing Model (CAPM), the Arbitrage Pricing Theory (APT), Options Theory and the BlackScholes (8-S) Option Pricing Model. The main conclusion of the study is that the main capital market theories and pricing models, as reviewed in the study, do provide a reasonably accurate description of reality, but a number of anomalies and controversial issues still need to be resolved. The main recommendation of the study is that research into these theories and models should continue unabated, while the specific recommendations in a South African context are the following: ( 1) the benefits of global diversification for South African investors should continue to be investigated; (2) the level and degree of efficiency of the JSE Securities Exchange SA (JSE) should continue to be monitored, and it should be established whether alternative theories to the EMH provide complementary or better descriptions of the efficiency of the South African market; (3) both the CAPM and the APT should continue to be tested, both individually and jointly, in order to better understand the pricing mechanism of, and risk/return relationship on the JSE; (4) much South African research still needs to be conducted on the efficiency of the relatively new options market and the application of the B-S Option Pricing Model under South African conditions. / Financial Accounting / M. Com. (Accounting)

The study investigates whether the main capital market theories and pricing models provide a reasonably accurate description of the working and efficiency of capital markets, of the pricing of shares and options and the effect the risk/return relationship has on investor behaviour. The capital market theories and pricing models included in the study are Portfolio Theory, the Efficient Market Hypothesis (EMH), the Capital Asset Pricing Model (CAPM), the Arbitrage Pricing Theory (APT), Options Theory and the BlackScholes (8-S) Option Pricing Model. The main conclusion of the study is that the main capital market theories and pricing models, as reviewed in the study, do provide a reasonably accurate description of reality, but a number of anomalies and controversial issues still need to be resolved. The main recommendation of the study is that research into these theories and models should continue unabated, while the specific recommendations in a South African context are the following: ( 1) the benefits of global diversification for South African investors should continue to be investigated; (2) the level and degree of efficiency of the JSE Securities Exchange SA (JSE) should continue to be monitored, and it should be established whether alternative theories to the EMH provide complementary or better descriptions of the efficiency of the South African market; (3) both the CAPM and the APT should continue to be tested, both individually and jointly, in order to better understand the pricing mechanism of, and risk/return relationship on the JSE; (4) much South African research still needs to be conducted on the efficiency of the relatively new options market and the application of the B-S Option Pricing Model under South African conditions. / Financial Accounting / M. Com. (Accounting)

Le premier chapitre examine les caractéristiques statistiques à long terme des rendements financiers en France et aux USA. Les propriétés des différents actifs font apparaître qu’à long terme les actions procurent un risque sensiblement moins élevé. En outre, les propriétés de retour à la moyenne des actions justifient qu’elles soient utilisées dans une stratégie de cycle de vie comme « option par défaut » de plans d’épargne retraite. Le chapitre deux fournit une explication au débat sur l'hypothèse d’efficience des marchés. La cause du débat est souvent attribuée à la petite taille des échantillons et à la faible puissance des tests statistiques dédiés. Afin de contourner ce problème, nous utilisons l'approche développée par Campbell et Viceira (2005) qui utilisent une méthode VAR pour mettre en évidence l’existence de retour vers la moyenne dans le cours des actifs risqués.Le troisième chapitre évalue la vitesse de convergence des cours des actions. Un moyen classique pour caractériser la vitesse de retour vers la moyenne est la « demi-vie ». En comparant les indices boursiers de quatre pays développés (États-Unis, Royaume-Uni, France et Japon) sur la période 1950-2014, nous établissons une vitesse de convergence significative, avec une demi-vie entre 4,0 et 5,8 ans.Le dernier chapitre présente les résultats d'un modèle conçu pour étudier les interactions entre la démographie et les régimes de retraite. Afin d’étudier les risques inhérents à l’utilisation des revenus du capital pour financer les retraites, nous utilisons un « Trending OU process » au lieu d’un MBG classique pour modéliser les rendements. Pour un épargnant averse au risque le marché pourrait concurrencer les régimes par répartition. / Chapter one examines the long run statistical characteristics of financial returns in France and the USA for selected assets. This study clearly shows that the returns’ distributions diverge from the Gaussian strategy as regards longholding periods. Thereafter we analyze the consequences of the non-Gaussian nature of stock returns on default-option retirement plans.Chapter two provides a reasonable explanation to the strong debate on the Efficient Market Hypothesis. The cause of the debate is often attributed to small sample sizes in combination with statistical tests for mean reversion that lackpower. In order to bypass this problem, we use the approach developed by Campbell and Viceira (2005) who have settled a vectorial autoregressive methodology (VAR) to measure the mean reversion of asset returns.The third chapter evaluates the speed of convergence of stock prices. A convenient way to characterize the speed of mean reversion is the half-life. Comparing the stock indexes of four developed countries (US, UK, France and Japan) during the period 1950-2014, we establish significant mean reversion, with a half-life lying between 4,0 and 5,8 years.The final chapter provides some results from a model built in order to study the linked impacts of demography and economy on the French pension scheme. In order to reveal the risks that are contained in pension fund investment, we use a Trending Ornstein-Uhlenbeck process instead of the typical GBM for modeling stock returns. We find that funded scheme returns, net of management fees, are slightly lower thanthe PAYG internal rate of return.

Bakgrund: Kapital på börsen förflyttas fram och tillbaka mellan olika tillgångar, vilket ären naturlig del av diversifieringen i portföljer. När osäkerheten ökar i marknaden väljerinvesterare normalt att förflytta kapital från aktier till säkrare tillgångar som exempelvisobligationer, vilket beskrivs som Flight to Quality (FTQ). Däremot har räntorna efter denglobala finanskrisen 2008 varit historiskt låga och under vissa perioder negativa, vilket i sintur försvagar förflyttningen. Sverige har här utmärkt sig, genom att till skillnad från USA,fortsatt att sänka räntan och legat på låga nivåer under en väldigt lång tid. Därmed uppstårfunderingar kring hur förflyttningar av kapital har sett ut i Sverige de senaste 30 åren, samthur det senaste lågränteklimatet påverkar. Syfte: Syftet med studien är att undersöka förhållandet mellan avkastningen på noteradeobligationer och aktier i Sverige från 1993 till 2022. Studien ska även undersöka hur enlågräntemiljö påverkar förhållandet. Metod: OMXSPI samt BMSD10Y har använts för att beräkna avkastningen på aktierrespektive obligationer från databaserna Refinitiv Eikon samt Refinitiv Datastream. Urvaleti studien uppgick till 7271 respektive 1526 observationer. Genom en kvantitativ metod ochdeduktiv ansats har studien utgått från teorin gällande FTQ för att undersöka hurkorrelationen förändrats. Vidare har regressioner använts för att säkerställa påverkan pånivån av korrelationen samt hur ett lågränteklimat påverkar styrkan i FTQ. Slutsats: Studiens resultat påvisar att korrelationen mellan aktier och obligationer undertidsperioden har varit svagt negativ med fyra olika strukturella förändringar under perioden.Vidare visar studiens resultat att ett lågränteklimat under perioden har försvagat styrkan iFTQ:er som inträffat i Sverige mellan 1993 och 2022. Studien bidrar till litteraturen inomområdet korrelation mellan aktier och obligationers avkastningar, samt litteraturen kringlågränteklimats påverkan på finansiella marknader. / Background: Capital on the stock exchange is moved back and forth between differentassets, which is a natural part of the diversification of portfolios. When uncertainty increasesin the market, investors normally choose to move capital from equities to safer assets such asbonds, which is described as Flight to Quality (FTQ). On the other hand, interest rates afterthe global financial crisis in 2008 have been historically low and in some cases negative,which in turn weakens the capital movement. Sweden has distinguished itself, in that unlikethe United States, it has continued to lower its interest rates and have kept them at low levelsfor a very long time. This raises concerns about how capital movements over the past 30 yearshave developed in Sweden, and how the recent low interest rate climate is affecting. Purpose: The purpose of the study is to investigate the relationship between returns onstocks and bonds in Sweden from 1993 to 2022. The study will also investigate how a lowyield environment effects the relationship. Method: OMXSPI and BMSD10Y have been used to calculate the return on stocks andbonds from the databases Refinitiv Eikon and Refinitiv Datastream, respectively. The samplein the study amounted to 7271 and 1526 observations. Through a quantitative method anddeductive approach, the study has been based on the theory regarding FTQ to investigatehow the correlation has changed. Furthermore, regressions have been used to ensure theimpact on the level of the correlation and how a low interest rate climate affects the strengthof the FTQ. Conclusion: The result shows a weak negative correlation between returns on stocks andbonds during the time period, with four different structural breaks during the period.Furthermore, the results show that a low yield environment has weakened the strength of theFlights to Quality that have occurred in Sweden between 1993 and 2022. This studycontributes to the literature in the field of stock-bond return correlation and the field of lowyield effects on financial markets.