<p>Bakgrund: Många företagsskandaler har drabbat ett flertal länder runt om i världen och det är en av orsakerna till att många länder har skapat koder för bolagsstyrning. Sverige är inte heller förskonat från skandaler och uppmärksamheten kring bolagsstyrningsfrågor har intensifierats på senare tid. Kodgruppen, en grupp tillsatt av regeringen, skapade Svensk Kod för Bolagsstyrning som trädde i kraft den 1 juli 2005. Koden har bl a som syfte att ge riktlinjer för bolagets rapportering till kapitalmarknad och ägare.</p><p>Syfte: Syftet med uppsatsen är att granska 50 bolagsstyrningsrapporter och i dem ta fram de vanligaste avvikelserna från Koden och de mest frekventa förklaringarna till dessa. Vidare undersöks graden av tydlighet i informationen i bolagsstyrningsrapporterna avseende Kodens tillämpning hos de berörda företagen. Avslutningsvis undersöks hur stor andel av rapporterna som är granskade av revisor eller inte.</p><p>Teori: Den teoretiska referensramen utgår ifrån corporate governance,</p><p>informationsasymmetri samt intressentteorin.</p><p>Metod: Den vetenskapliga metoden för uppsatsen är kvantitativ, systematiska observationer har utförts i 50 bolagsstyrningsrapporter för att därefter presenteras i diagram och tabeller. Den kvantitativa metoden valdes för att få en generell bild av tillämpningen av Koden.</p><p>Slutsats: Utifrån författarnas granskning kan konstateras att bolagen har en hög ambition gällande tillämpningen av Koden vilket kan utläsas av det låga antalet avvikelser per bolag. Vidare påvisar det låga avvikelseantalet att företagen har gjort en ansträngning för en ökad öppenhet och transparens gentemot aktieägarna. Bolagsstyrningsrapporterna har således gett aktieägarna och övriga intressenter en större insikt i företagens bolagsstyrning och därmed reduceras informationsasymmetrin.</p><p>Nyckelord: Svensk Kod för Bolagsstyrning, bolagskod, bolagsstyrning,</p><p>informationsasymmetri.</p> / <p>Background: Many scandals within big corporations have occurred in several countries and that is one of the reasons countries have created codes for corporate governance. Sweden is not spared from scandals and the debate about corporate governance has been intensified the last couple of years. A group called Kodgruppen, appointed by the Government, has created the Swedish Code of Corporate Governance which took effect 1 July, 2005. The purpose of the Code, among other things, is to give the concerned corporations guidelines about the content in the reports to the capital market and the shareholders.</p><p>Purpose: The purpose of this essay is to review 50 Swedish stock exchange corporations’ reports of corporate governance and from these portray the most frequent deviations from the Swedish Code and the most common explanations to these. The study also looks into the clearness of the information given in the reports regarding the implementation of the Code. Further the paper examines how many of the companies that had their corporate governance report reviewed by an auditor.</p><p>Theory: The theoretical frame of reference is corporate governance, information asymmetry and the stakeholder theory.</p><p>Method: The scientific method for the paper is quantitative, systematic observations have been done of 50 corporate governance reports which are presented in diagrams and tables. The quantitative method was chosen to describe a general situation of the application of the Code.</p><p>Conclusion: From the basis of the author’s review we can establish that the companies have a high ambition in the application of the Code which can be understood from the low number of deviations per company. Furthermore shows the low number of deviations that the</p><p>companies have made an effort for more openness and transparency towards the stockholders. The corporate governance reports have thus given the shareholders and other stakeholders a greater insight in the companies’ corporate governance and with that reduces the information asymmetry.</p><p>Key words: Swedish Code of Corporate Governance, code of corporate governance, corporate governance, information asymmetry.</p>

Syftet med denna uppsats har varit att undersöka i vilken utsträckning företag på Stockholmsbörsen följer IAS 36 p. 134, vilket behandlar nedskrivningsprövning av goodwill. Även vilka faktorer som påverkar denna informationsutgivning analyseras. / The purpose of the thesis is to investigate to which extent companies on the Stockholm stock exchange comply with IAS 36 p. 134, and which factors that may affect the compliance with IAS 36 p. 134.

Bakgrund: Många företagsskandaler har drabbat ett flertal länder runt om i världen och det är en av orsakerna till att många länder har skapat koder för bolagsstyrning. Sverige är inte heller förskonat från skandaler och uppmärksamheten kring bolagsstyrningsfrågor har intensifierats på senare tid. Kodgruppen, en grupp tillsatt av regeringen, skapade Svensk Kod för Bolagsstyrning som trädde i kraft den 1 juli 2005. Koden har bl a som syfte att ge riktlinjer för bolagets rapportering till kapitalmarknad och ägare. Syfte: Syftet med uppsatsen är att granska 50 bolagsstyrningsrapporter och i dem ta fram de vanligaste avvikelserna från Koden och de mest frekventa förklaringarna till dessa. Vidare undersöks graden av tydlighet i informationen i bolagsstyrningsrapporterna avseende Kodens tillämpning hos de berörda företagen. Avslutningsvis undersöks hur stor andel av rapporterna som är granskade av revisor eller inte. Teori: Den teoretiska referensramen utgår ifrån corporate governance, informationsasymmetri samt intressentteorin. Metod: Den vetenskapliga metoden för uppsatsen är kvantitativ, systematiska observationer har utförts i 50 bolagsstyrningsrapporter för att därefter presenteras i diagram och tabeller. Den kvantitativa metoden valdes för att få en generell bild av tillämpningen av Koden. Slutsats: Utifrån författarnas granskning kan konstateras att bolagen har en hög ambition gällande tillämpningen av Koden vilket kan utläsas av det låga antalet avvikelser per bolag. Vidare påvisar det låga avvikelseantalet att företagen har gjort en ansträngning för en ökad öppenhet och transparens gentemot aktieägarna. Bolagsstyrningsrapporterna har således gett aktieägarna och övriga intressenter en större insikt i företagens bolagsstyrning och därmed reduceras informationsasymmetrin. Nyckelord: Svensk Kod för Bolagsstyrning, bolagskod, bolagsstyrning, informationsasymmetri. / Background: Many scandals within big corporations have occurred in several countries and that is one of the reasons countries have created codes for corporate governance. Sweden is not spared from scandals and the debate about corporate governance has been intensified the last couple of years. A group called Kodgruppen, appointed by the Government, has created the Swedish Code of Corporate Governance which took effect 1 July, 2005. The purpose of the Code, among other things, is to give the concerned corporations guidelines about the content in the reports to the capital market and the shareholders. Purpose: The purpose of this essay is to review 50 Swedish stock exchange corporations’ reports of corporate governance and from these portray the most frequent deviations from the Swedish Code and the most common explanations to these. The study also looks into the clearness of the information given in the reports regarding the implementation of the Code. Further the paper examines how many of the companies that had their corporate governance report reviewed by an auditor. Theory: The theoretical frame of reference is corporate governance, information asymmetry and the stakeholder theory. Method: The scientific method for the paper is quantitative, systematic observations have been done of 50 corporate governance reports which are presented in diagrams and tables. The quantitative method was chosen to describe a general situation of the application of the Code. Conclusion: From the basis of the author’s review we can establish that the companies have a high ambition in the application of the Code which can be understood from the low number of deviations per company. Furthermore shows the low number of deviations that the companies have made an effort for more openness and transparency towards the stockholders. The corporate governance reports have thus given the shareholders and other stakeholders a greater insight in the companies’ corporate governance and with that reduces the information asymmetry. Key words: Swedish Code of Corporate Governance, code of corporate governance, corporate governance, information asymmetry.

This thesis investigates whether IFRS adoption has led to an increase in the relevance of accounting information for investment decisions. Furthermore, the effects of IFRS are implicitly compared across accounting traditions. As such,  the effects of IFRS on the “quality” of financial reporting are measured based on the cases of listed firms in Germany and listed firms in the UK. This study approaches the effects of IFRS on the quality of financial reporting from two angles. First a review of the academic literature is done to determine whether there has been a general consensus about the effects of IFRS adoption on financial reporting of listed firms in Germany and the UK. As a result of this literature study, a number of propositions are deduced about the effects of IFRS. Subsequently, the investigation of the effects of IFRS takes a statistical perspective. Financial and accounting data are obtained for two samples, one of German listed firms and another of UK listed firms. A number of empirical models are used to determine the quality of financial reporting, including the earnings-returns association (Lev ,1989; Lev &amp; Zarowin, 1999), asymmetric sensitivity of earnings and asymmetric persistence of earnings (Basu, 1997), and the market-to-book ratios (Roychowdhury &amp; Watts, 2003). Additionally, a new tool is introduced for a joint interpretation of the econometric test results, leading potentially to a new method of financial report analysis under dynamic regulatory conditions. Significant statistical evidence is found suggesting a drastic reduction (to the point of complete elimination) in income smoothing in Germany corresponding to the transition from the German national GAAP to IFRS. Additionally, with the introduction of IFRS, the information content of accounting earnings in German firms appears to have increased substantially, while market-to-book ratios have converged towards “1”. On the other hand, the introduction of IFRS in the UK corresponds to statistical evidence consistent with a shift from asymmetric timeliness of earnings under UK GAAP to a significant downward bias in earnings under IFRS. The study also shows significant inter-industry differences in the effects of IFRS that suggest that the inconsistencies in the results of previous studies may have been due to the significant noise created by diverse samples, or due to biased industry representations in the data.

Bakgrund och problem: Det föreligger en problematik i kreditbedömningsprocessen som berör svårigheten att bedöma ett  bolags värde samt dess återbetalningsförmåga. Vanligtvis värderas organisationer utefter sina finansiella rapporter men eftersom de inte alltid inkluderar immateriella tillgångar i form av intellektuellt kapital skapas en informationsasymmetri. Informationsasymmetrin kan vara en orsak till eventuella felbedömningar av ett företags riskutsatthet och framtida utveckling och således till ett nekande av sökt kredit. Forskare lägger skulden på redovisningssystemet men vi vill lyfta frågan om problemet även kan ligga i kreditbedömningsprocessen. Syfte: Syftet med föreliggande studie är att undersöka hur banker, i rollen som finansiärer, behandlar intellektuellt kapital hos kunskapsintensiva företag vid en kreditbedömning. Avsikten är att beskriva, tolka samt reflektera kring kreditprocessen för att påvisa vilken betydelse det intellektuella kapitalet har för kreditbeslutet. Metod/Empiri: Studien har utförts som en kvalitativ undersökning baserad på intervjuer och praktikfall. De fem storbankerna Danske Bank, Handelsbanken, Nordea, SEB och Swedbank har agerat respondenter. Efter sammanställningen av empiriunderlaget jämfördes svaren mot den teoretiska referensramen. Påträffade samband och avvikelser mellan empiri och teori har i ett logiskt resonemang fått utgöra studiens analys. Slutsatser: Resultatet av studien visar att studiens respondenter i kreditbedömningsprocessen beaktar avsevärt fler faktorer, som teoretiskt benämns intellektuellt kapital, än vad de är medvetna om. Intellektuellt kapital har därmed en anmärkningsvärd inverkan på kreditbeslutet, även om det inte enskilt är avgörande för beslutet. Vidare visar studien att den främsta problematiken med intellektuellt kapital i kreditbedömningsprocessen rör värderingssvårigheten. / Background and problem: There is a problem in the credit valuation process relating to the difficulty of estimating the value of a company and its repayment ability. Generally organizations are valued by their financial statements but since financial statements not always include intangible assets in forms of intellectual capital an information asymmetry is created. The information asymmetry may be a reason for an incorrect assessment of a company’s risk exposure and future development and thus to a refusal of sought credit. Researchers blame the accounting system but we wish to raise the question whether the problem also may lie in the credit valuation process. Aim: The purpose of this master thesis is to investigate how banks treat intellectual capital in knowledge-intensive firms in a credit valuation process. The aim is to describe, interpret and reflect around the credit valuation process in order to demonstrate the importance of intellectual capital for the credit decision. Method/Empirical data: The study was conducted as a qualitative study based on interviews and case studies. Five of the largest banks in Sweden - Danske Bank, Handelsbanken, Nordea, SEB and Swedbank - have acted as respondents. After compiling the empirical material the responses were compared with the theoretical framework. Located relations and differences between empiricism and theory constitute the analysis of the study. Conclusions: The results of this study show that the respondents in the credit valuation process examines significantly more factors, which in theory is defined intellectual capital, than they are aware of. Intellectual capital has thus a remarkable impact on the credit decision, although it does not individually determine the decision. The study also shows that the main problem with intellectual capital in the credit valuation process is the difficulty of valuation.

中國大陸自1978年改革開放以來經濟不斷朝市場化方向邁進，近年來小微企業逐漸成為中國大陸經濟結構轉型的因素以及經濟發展的動能。然而計畫經濟時期資源分配集中在大型國有企業使得小微企業資金取得困難，小微企業在現階段帶動中國大陸經濟轉型與發展，但卻面臨資金借貸的資訊不對稱問題。在小額借貸市場失靈現象下，中國大陸新興的小額借貸模式，如P2P網路借貸、小額貸款公司等如雨後春筍般出現。 本論文探討中國大陸小額借貸金融體系的市場失靈問題，以資訊不對稱理論分析微型貸款融資模式與網路金融機構的創新途徑如何解決此困境。並以阿里巴巴集團的螞蟻金服為個案延伸探討。 資訊不對稱理論為本論文之理論基礎，並以文獻分析與統計資料分析兩模式分析中國大陸當前的金融環境。在個案分析部分將阿里巴巴集團的螞蟻金服與P2P網路借貸平台、傳統銀行業小額貸款業務的運作模式以及風險機制等做比較，並以風險機制進一步探討資訊不對稱理論的作用。 本論文最後提出三項看法作為結論，包括：創新的小額借貸模式得以降低資訊不對稱、中國大陸網路經濟迅速發展加快小微企業與金融業創新、小額貸款模式本身缺失。 / Marketization in China began after its economic reforms started in 1978. In recent years, micro and small enterprises have become a factor of economic transformation and a momentum of economic growth in China. While most resources were allocated to large, state businesses in the planned economy period, it was difficult for micro and small enterprises to access relevant resources. Although micro and small enterprises are driving the Chinese economic transformation, they are facing the loan information asymmetry problem. As the micro credit market is malfunctioning, emerging micro credit models, such as P2P internet lending and micro lending companies, are springing up like mushrooms. This paper investigates the malfunction of China’s micro credit market analyzed how of the innovation of micro credit models and internet financial institutions solve this problem with information asymmetry theory. An extended investigation was conducted with Ant Financial of Alibaba Group as an example. Information asymmetry is the theoretical background of this paper. This paper analyzed China’s present financial situation with literature and statistical analyses. This study also compared the operating model and risk control for micro credit between Ant Financial, P2P internet lending, and traditional banks in the case study and further reviewed the effect of information asymmetry in risk control. In conclusion, this study found that (1) innovative micro credit model could reduce information asymmetry; (2) the rapid development of China’s internet economy has accelerated the innovation of local micro and small enterprises and the financial industry, and (3) the problems in current micro credit models.

Globalization has led to the growth of international financial markets, as one of the results, the EU adopted IFRS in 2005 to meet the need of accounting globalization and harmonization. This action has triggered a debate about whether the adoption of IFRS is beneficial to accounting quality and information comparability. Meanwhile, China, playing a key role in the global economic development stage, realizes the importance of accounting harmonization and attempts to move towards the IFRS as well. However, to reach the goal that the Chinese companies produce financial statements that are the same as those that apply IFRS, there is still a long way to go. The purpose of this thesis is to examine whether the adoption of IFRS by EU has enhanced the quality of financial reporting and accounting information comparability. Additionally, the thesis further identified the seminal undertakings for the convergence of IFRS in Europe and pointed out the implication for China’s convergence with IFRS. The empirical findings in this thesis were obtained through qualitative interviews. The empirical findings suggest that accounting quality and information comparability has been enhanced with EU’s strong and full enforcement with IFRS. With the confidence in IFRS which is gained from the success of the EU’s adoption of IFRS, a coherent result was found that the convergence towards IFRS would also benefit China in accounting quality and information comparability, and further lead to more international investments. However, when it comes to the question whether China should emulate EU’s example to adopt IFRS directly or keep CAS (Chinese Accounting Standards) which is similar to IFRS, two mixed opinions were obtained basically from Europe side and China side. Through in-depth analysis with these empirical findings, the conclusion is that it is necessary for China to take steps to build intensive programs to enhance its capacity of the adoption of IFRS, so that it could adapt itself to the fact that the IFRS is already making its way around the world as a single set of high quality global accounting standards.

本文嘗試以訊息理論中的代理模型來探討台灣在今年(2005,民國94年)將承銷舊制改為新制，對國內初級市場以及當中參與者(包括初次上市公司、公司原大股東、投資人以及承銷商四者)的影響。 經過本文從模型建立、推導和結果之比較分析後發現，事實上，金管會所欲解決國內初級市場的許多不合理問題，最後可以歸納成為兩大問題：一、如何讓承銷商解決公司與投資人之間資訊不對稱的問題？該問題表現在承銷價被低估，或是公司欺騙投資人其真實獲利類型來取得額外之獲利上。二、如何讓公司可以在上市時，真正拿到所募集之資金並且做妥善運用？該問題表現在承銷價被高估，或是原大股東在公司上市時賣老股所能得到之獲利上。 透過本文模型證明，藉由觀察新舊制下承銷價、原大股東以及公司獲利來源的變化可知，新制實施的各種長短期措施，例如短期下強制公司必須以新股承銷(解決問題一)、要求承銷商運用專業審核監督公司的營運概況(解決問題二)，長期下則透過承銷商分級管理制度(解決問題二)等，只要金管會確實執行，的確能讓初級市場最主要的兩大問題得到解決，最終還可達到完全資訊狀態。 但是，本文觀察發現，上半年整個初級市場的概況只能以「冷清」兩字來形容，因此繼續從新制實施的短期角度來看，考慮初級市場四種參與者所增加的各項成本，包括發行成本、資訊揭露成本等，以及其在適應新制時所造成新的衝擊與影響，包括公司額外募得之資金運用不當、每股盈餘遭稀釋之衝擊等等之後，本文發現經過初級市場四種參與者的交互影響，則最壞情況為發生「短期獲利低類型公司被逐出初級市場」的現象，並導致初級市場失靈而失去其所能帶給公司作為籌資管道之功能，這便可解釋為何初級市場近來會有如此冷清的情況。 因此本文建議，未來新制應做適度修正，例如降低公司上市時的成本、提供更大的誘因讓承銷商願意承做上市案件，避免初級市場發生失靈的可能；最後若再加上金管會確實長期下來公平客觀的執行承銷商分級管理制度，解決承銷商過度競爭之情況、讓投資人有信心願意相信承銷商會替其解決資訊不對稱的問題，則新制對整個初級市場以及參與者而言，將可帶來正面的效果與助益。 事實上，本文在研究過程中發現，國內承銷制度變革多著重於增加消極外部監督力量，並強調解決投資人與公司之間資訊不對稱的問題；但是本文以為，未來承銷制度還可走向實施能夠創造積極且為內部自發性監督力量的措施，且亦應設法解決承銷商與投資人、承銷商與公司之間資訊不對稱的問題才是，因此本文提出：一、在讓承銷商恢復專業方面，除了先前所提減少消極外部監督力量之衝擊，應設法再擴大承銷商的獲利來源和增加其本身積極內部監督之力量，例如培養出特有的服務項目尋求專業化或是選擇提供多種服務達到範疇經濟效果，以及品牌建立等；二、在解決公司與投資人之間資訊不對稱的問題方面，除了透過承銷商，本文認為還可藉由公司本身品牌之建立創造出自我監督力量，以及讓國內投資人從以散戶為主體到組成團體，形成類似法人之概念創造另一個外部監督的力量。三、在讓公司可以真正拿到上市時所募集之資金並做妥善運用方面，除了新股發行，本文建議，公司在使用新制上市時應了解到不能再沿用舊制的思考模式，須事先規劃如何降低新制帶給公司的衝擊，至於上市後，尚須透過完善的公司治理制度，來健全整個公司資金運用情形，因此金管會在對承銷制度進行改革的同時，也應考慮是否亦須適時修改出更完善的公司治理制度，藉由同時對公司上市前後之行為做完善的規範，相信能讓承銷制度的改革達成更顯著的效果。 藉由以上三方面之建議，本文希望能夠更迅速有效的解決國內當前初級市場所存在的不合理問題，並讓其在未來朝著更健全的方向發展，進而使得國內整個資本市場達成質與量皆提升的目標。

Au cours de la dernière décennie, les chercheurs se sont intéressés au comportement de l'investisseur sur les marchés boursiers. Nombreuses théories en psychologie et sociologie sont mobilisées en finance comportementale pour dépasser les limites de l'hypothèse de l’efficience des marchés et expliquer la fragilité des marchés financiers. En analysant le comportement grégaire (mimétisme), les chercheurs tentent d'expliquer les anomalies et les grands mouvements du marché. Le comportement grégaire peut être décrit comme la tendance d'un investisseur ou d’un groupe d'investisseurs, à imiter les actions des autres acteurs du marché, ou à suivre la tendance du marché. Notre première étude examine la présence du comportement grégaire, en se concentrant sur le marché boursier français, au niveau du marché et au niveau des secteurs. Nous étudions le mimétisme selon différentes conditions macroéconomiques. Nous testons aussi l'existence du mimétisme au cours de la dernière période de crise financière et pendant les périodes caractérisées par des volumes (élevés ou faibles) de volatilité et de volume de transaction. En utilisant le modèle de CH 95, nous ne détectons pas de comportement grégaire, à la fois au niveau du marché qu’au niveau des secteurs, pendant les mouvements de marché extrêmes. Les modèles de CCK 2000 et Hwang et Salmon 2004 montrent des résultats mitigés. Même lorsque le comportement grégaire est détecté au niveau du marché, les secteurs se comportent différemment. La mesure que nous extrayons du state-space model montre différents niveaux de mimétisme dans les secteurs. La deuxième étude examine le mimétisme, sur les marchés boursiers américains et chinois, en introduisant une nouvelle dimension : l'asymétrie d'information. Nous utilisons plusieurs mesures de la disponibilité de l'information : la politique de dividende, le bid-ask spread, la taille de l'entreprise, la sophistication du marché, ainsi que l'état du marché (pré, post et pendant la période de crise). Cette étude nous permet d’analyser le mimétisme dans différents contextes selon la disponibilité de l'information. Elle permet de vérifier si le mimétisme est plus prononcé dans un contexte d'asymétrie d'information élevée. D’une part, les résultats du modèle de CH 95 ne montrent aucune preuve de mimétisme quel que soit le niveau d'asymétrie d'information entre les entreprises et les investisseurs, à la fois pour les marchés américain et chinois. D'autre part, le modèle CCK 2000 détecte des différences de niveau de mimétisme dans le marché boursier chinois en fonction du niveau d'asymétrie d'information. Les résultats suggèrent que les marchés émergents sont touchés par le mimétisme pendant la période de crise, quelle que soit la taille de l'entreprise. Enfin, le modèle de Hwang et Salmon 2004 montre différents niveaux de mimétisme dans les marchés américain et chinois, en fonction du niveau d'asymétrie d'information. Il est intéressant pour la recherche sur la modélisation des marchés boursiers d’examiner le comportement grégaire des investisseurs. De la même façon, les décideurs politiques pourraient être intéressés par les effets perturbateurs potentiels du mimétisme sur les marchés financiers. / Over the last decade, the academic research has highly focused on examining the investor’s behavior in stock markets. Many theories in psychology and sociology are used in the so called “Behavioral Finance” in order to explain the limits of the efficient market hypothesis and the financial market fragility. By analyzing the herding behavior, the researchers try to explain the market anomalies and the large market movements. Herding behavior can be described as the tendency of an investor, or a group of investors, to imitate the actions of other market participants, or to follow the market movement. Our first study examines the presence of herding behavior, focusing on the French stock market, at both market and sector levels. We investigate herding during different macroeconomic conditions. We also test the existence of herding during the last financial crisis period, and during the periods characterized by high or low volatility and transaction volumes. Using the CH 95 model, we do not observe herding behavior, both in market and sector levels, during extreme market movements. The CCK 2000 and Hwang and Salmon 2004 models show mixed results. Even when herding exists in the market level, various sectors behave differently. The measure we extract from the state-space model shows different patterns of herding at the sector level. The second study examines the investors’ incentives behind herding, in the US and Chinese stock markets, by introducing a new dimension, which is the information asymmetry. Using several proxies for information availability, such as dividend policy, bid ask spread, firm size and market sophistication along with considering the market condition (pre, post and during crisis period), this study allows us to investigate herding in different contexts of information availability, and to examine if herding is more pronounced in a high information asymmetry context. Findings of CH 95 model show no evidence of herding regardless of the level of information asymmetry between firms and investors in both the US and Chinese stock markets. On the other hand, the CCK 2000 model detects herding differences in the Chinese stock market depending on the information asymmetry level. The findings suggest that the emerging markets are affected by herding during the crisis period, regardless of the firm size. Finally, the Hwang and Salmon 2004 model shows different herding patterns in the US and Chinese stock markets depending on the information asymmetry level. Examining the herding behavior is interesting for the research in the market modeling field along with policymakers who may be interested in investigating the potential disturbing effects of herding on stock markets.

Les modèles d’équilibre à anticipations rationnelles (EAR) ont été considérablement développés ces 40 dernières années. Cependant, encore relativement peu d’avancées ont été réalisées quant à leurs applications empiriques, les signaux privés étant inobservables. Nous proposons une nouvelle méthodologie, fondée théoriquement, pour reconstituer ces signaux et ainsi parfaitement déduire toute l’information. Ce qui nous permet de construire le portefeuille optimal des agents informés et d’explorer ses propriétés à travers trois études. Dans un premier article, nous montrons que les ordres soumis au carnet d’ordres (l’offre) et le prix d’équilibre qui en résulte constituent une statistique suffisante pour l’ensemble d’information agrégé. Nous expliquons comment extraire l’information contenue dans ces deux données, en utilisant les volumes réalisés (connus avec délai) comme proxy pour l’offre, et construire ex post le portefeuille conditionnel à l’information privée. Nous comparons ses performances avec le portefeuille optimal des agents non-informés obtenu ex ante à partir des prix. Dans un second article, nous dérivons le portefeuille optimal des investisseurs informés en explorant une spécification différente du bruit. Constitué dans la première étude par une offre fournie de façon exogène par des noise traders, nous considérons à présent que les investisseurs informés et non-informés échangent entre eux. Ils sont initialement dotés d’une quantité aléatoire d’actifs risqués et échangent rationnellement sur le marché boursier pour se couvrir et spéculer sur leur information. Nous démontrons qu’il est alors nécessaire d’utiliser la partie des volumes relative à de l’information, déterminée à partir d’une mesure de la probabilité d’échanges informés, à la place des volumes totaux. A cause des contraintes et de la complexité de cette mesure, nous trouvons qu’utiliser les volumes totaux constitue le meilleur choix, du moins jusqu’à ce qu’une meilleure mesure soit trouvée. Enfin, dans une troisième étude, nous utilisons le portefeuille des agents informés pour tester le modèle d’évaluation des actifs financiers (MEDAF) conditionnel, à la place d’un indice boursier pondéré selon les capitalisations traditionnellement utilisé comme proxy pour le portefeuille de marché. Nous démontrons que conditionner à l’information privée permet d’estimer le vrai bêta, ainsi que la prime de risque du marché en isolant la prime de risque d’information qu’un indice boursier est incapable de distinguer. / Rational expectation equilibrium (REE) models were considerably developed over the past 40 years. However, still relatively little has been done on their empirical applications, private signals being unobservable. We propose a new methodology, theoretically premised, to reconstitute these signals and thus perfectly infer all the information. This allows us to build the optimal informed investors’ portfolio and explore its properties through three studies. In the first paper, we show, based on a REE model, that the orders entered into the order book (supply) and the resulting equilibrium price constitute a sufficient statistic for the aggregate information set. We explain how to extract the information contained in these two data, using realized volumes (known with delay) as proxy for the supply, and to construct ex post the portfolio conditional on private information. We compare its performance with the optimal uninformed agents’ portfolio obtained ex ante from prices. In a second paper, we derive the optimal informed investors’ portfolio by investigating a different specification for the noise. Constituted in the first study by a supply exogenously provided by noise traders, we now consider that informed and uninformed investors trade amongst themselves. They are initially endowed with a random quantity of risky assets and have both risk-sharing and informational motives to trade rationally on the stock market. We demonstrate that we must use information-related volumes, determined with a measure of the probability of informed trades, instead of total volumes. Due to the constraints and complexity of this measure, we found that using total volumes constitutes the best choice, at least until a better measure is found. Finally, in a third study, we use the informed agents’ portfolio to test the conditional capital asset pricing model (CAPM), instead of a value-weighted stock index traditionally used as proxy for the market portfolio. We show that conditioning on private information allows estimating the real beta, as well as the market risk premium by isolating the information risk premium that an index is unable to distinguish.