scholarly journals Martingales, Efficient Market Hypothesis and Kolmogorov’s Complexity Theory

2011 ◽  
Vol 2 (6) ◽  
pp. 252-258
Author(s):  
Amaresh Das
Keyword(s):  
Time Series ◽  
Financial Markets ◽  
Stock Returns ◽  
Complexity Theory ◽  
Efficient Market Hypothesis ◽  
Market Theory ◽  
Efficient Market ◽  
Price Changes ◽  
Efficient Market Theory ◽  
Theoretical Considerations

Efficient market theory states that financial markets can process information instantly. Empirical observations have challenged the stricter form of the efficient market hypothesis (EMH). These empirical observations and theoretical considerations show that price changes are difficult to predict if one starts from the time series of price changes. This paper provides an explanation in terms of algorithmic complexity theory of Kolmogorov that makes a clearer connection between the efficient market hypothesis and the unpredictable character of stock returns.

scholarly journals EMT and Political Reform Effects on Chinese Markets: A Literature Review

2021 ◽  
Author(s):  
Luigi Gallo
Keyword(s):  
Literature Review ◽  
Financial Markets ◽  
Political Reform ◽  
Market Theory ◽  
Efficient Market ◽  
Efficient Market Theory ◽  
Chinese Markets ◽  
Analyse Data ◽  
Over Time

The objective of this paper is to analyse the literature on and the evolution of the analysis of Chinese financial markets over time. Seven papers, based mainly on Efficient Market Theory (Fama, 1998) and the correlation between different markets, published in the years 1999-2019, have been selected and compared as they analyse data taken from the Shenzhen and Shanghai markets.

scholarly journals Some of the unanswered questions in finance

2006 ◽  
Vol 53 (2) ◽  
pp. 223-230
Author(s):  
Dragana Djuric
Keyword(s):  
Financial Markets ◽  
Portfolio Optimization ◽  
Portfolio Theory ◽  
Economic Factors ◽  
Theoretical Base ◽  
Market Theory ◽  
Efficient Market ◽  
Efficient Market Theory ◽  
Substantial Progress ◽  
Behaviorist Theory

A very dynamic development of finance in the last 50 years is inter alia probably due to experiments and innovations in this field. Previously theoretical base could not explain and predict movements especially in volatile times. "The new finance" appeared 50 years ago (portfolio theory CAPM, the efficient market theory, M&M theorem) and made substantial progress in understanding movements in globalized and internationalized financial markets. However, many questions remain open. The author tries to put emphasis on some of these questions, perfectly aware that these are not the only ones. Unresolved questions are related to company's aims, project's risks, degree of portfolio optimization, importance of liquidity, dividend policy, as well as factors that determine M&A. As the "new finance" is not able to predict and explain volatile movements, a question that should be posed is whether it is appropriate to add some non-economic factors as the behaviorist theory suggests. Although the behaviorist theory is an important part of "new finance", it is unfortunately the only theory able to explain movements in volatile times. In conclusion, many questions still remain unanswered and wait for appropriate theoretical explanations.

scholarly journals Tropical forest dynamics correspond to fair games in economic theory of financial markets

2021 ◽  
Author(s):  
Yue Lin ◽  
James Rosindell ◽  
Uta Berger ◽  
Helge Bruelheide ◽  
Jens Kattge ◽  
...  
Keyword(s):  
Time Series ◽  
Complex Systems ◽  
Time Series Data ◽  
Dominant Role ◽  
Series Data ◽  
Market Theory ◽  
Efficient Market ◽  
Short Time Series ◽  
Efficient Market Theory ◽  
Short Time

Ecological and economic systems both comprise of autonomous adaptive agents. It is thus possible that similar mechanisms determine the organization of both these complex systems. Indeed several economic theories have already been successfully applied in an ecological context. Here we show that 'efficient market theory' in economics, where future earnings are distributed between competitors by a 'fair game', corresponds to fitness-equalizing mechanisms of coexistence in ecology. In contrast to stabilizing mechanisms, which promote coexistence by giving each species an equilibrium abundance that is resilient to perturbations, equalizing mechanisms promote coexistence without such resilience by minimizing the net fitness differences between species. However, identifying stabilizing and equalizing mechanisms from the short time-series data that are typically available in ecology is challenging. We used techniques from economics that are applied to collections of short time-series from a system. We found that observed species abundance dynamics in a neotropical forest are generally in agreement with efficient market theory implying a dominant role of equalizing mechanisms, which finding quantifies and supports what was generally believed about that specific forest system. Our study highlights that complex systems from ecology and economics share common features suggesting the possibility of further synergy between ecology and economics in future.

scholarly journals Die Johannesburgse Effektebeurs as rasionele kapitaalmark

1981 ◽  
Vol 12 (3) ◽  
pp. 53-59 ◽  
Author(s):  
Leon M. Brummer ◽  
Pieter J. Jacobs
Keyword(s):  
Stock Exchange ◽  
Weak Form ◽  
Efficient Market Hypothesis ◽  
Small Degree ◽  
Point Of View ◽  
Efficient Market ◽  
Price Changes ◽  
Economic Point ◽  
Johannesburg Stock Exchange ◽  
Measure Of Dependence

The Johannesburg Stock Exchange as an efficient market. Finality has not yet been reached on the question whether the Johannesburg Stock Exchange complies with the requirements of the efficient market hypothesis. The results of the research that are published in this article is therefore an attempt to make a contribution to the debate regarding the Johannesburg Stock Exchange as an efficient market. By way of serial correlations as well as runs tests an investigation was carried out into the behaviour of the prices of 94 quoted shares for the period 1970 to 1977. The results of the study give rise to the conclusion that the Johannesburg Stock Exchange does not statistically comply with the weak form of the efficient market hypothesis (the random walk hypothesis), as a measure of dependence between successive price changes was found. Seen from an economic point of view it is, however, doubtful whether investors could use this small degree of dependence between price changes to gain higher returns on share investments.Uitsluitsel met betrekking tot die mate waartoe die Johannesburgse Effektebeurs aan die vereistes vir 'n rasionele mark voldoen, is nog nie verkry nie. Die resultate wat in hierdie artikel voorkom is daarom 'n poging om 'n bydrae in die debat rakende die Johannesburgse Effektebeurs as 'n rasionele mark, te maak. 'n Ondersoek na die markpryse van 94 genoteerde aandele vir die periode 1970-77 is deur middel van reekskorrelasiekoeffisiente en die lopietoets uitgevoer. Die resultate van die studie gee aanleiding tot die gevolgtrekking dat die Johannesburgse Effektebeurs nie statisties aan die swak vorm van die rasionele markhipotese (die willekeurige beweging van markpryse) voldoen nie, aangesien 'n mate van afhanklikheid tussen opeenvolgende prysveranderings gevind is. Uit 'n ekonomiese oogpunt gesien is dit egter twyfelagtig of beleggers hierdie afhanklikheid sal kan aanwend om hoer opbrengste op aandelebeleggings te bewerkstellig.

Modern Financial Market Theory – A Critique Based on the Logic of Human Action

2021 ◽  
Vol 54 (3) ◽  
pp. 447-467
Author(s):  
Thorsten Polleit
Keyword(s):  
Decision Making ◽  
Financial Markets ◽  
Financial Market ◽  
Real World ◽  
Rational Expectation ◽  
Efficient Market Hypothesis ◽  
Human Action ◽  
Market Theory ◽  
Expectation Theory ◽  
Market Economics

The modern financial market theory (MFMT) – based on the efficient market hypothesis, rational expectation theory, and modern portfolio theory – has become the standard approach in financial market economics. In this article, the MFMT will be critically ­reviewed using the logic of human action (or: praxeology) as an epistemological meta­theory. It will be shown that the MFMT exhibits (praxeo-)logical deficiencies so that it cannot provide investors with well-founded decision-making support in real-world financial markets.

scholarly journals Price overreactions in the cryptocurrency market

2019 ◽  
Vol 46 (5) ◽  
pp. 1137-1155 ◽  
Author(s):  
Guglielmo Maria Caporale ◽  
Alex Plastun
Keyword(s):  
Regression Analysis ◽  
Transaction Costs ◽  
Design Methodology ◽  
Efficient Market Hypothesis ◽  
Efficient Market ◽  
Price Changes ◽  
Content Type ◽  
Dummy Variables ◽  
Price Patterns ◽  
Non Parametric

Purpose The purpose of this paper is to examine price overreactions in the case of the following cryptocurrencies: bitcoin, litecoin, ripple and dash. Design/methodology/approach A number of parametric (t-test, ANOVA, regression analysis with dummy variables) and non-parametric (Mann–Whitney U-test) tests confirm the presence of price patterns after overreactions: the next day price changes in both directions are bigger than after “normal” days. A trading robot approach is then used to establish whether these statistical anomalies can be exploited to generate profits. Findings The results suggest that a strategy based on counter-movements after overreactions is not profitable, whilst one based on inertia appears to be profitable but produces outcomes not statistically different from the random ones. Therefore, the overreactions detected in the cryptocurrency market do not give rise to exploitable profit opportunities (possibly because of transaction costs) and cannot be seen as evidence against the efficient market hypothesis (EMH). Originality/value The overreactions detected in the cryptocurrency market do not give rise to exploitable profit opportunities (possibly because of transaction costs) and cannot be seen as evidence against the EMH.

scholarly journals An Empirical Analysis of the Efficient Market Hypothesis in China’s Stock Market

2021 ◽  
Vol 4 (3) ◽  
pp. 1-5
Author(s):  
Jiaxuan Xu
Keyword(s):  
Stock Market ◽  
Financial Markets ◽  
Empirical Research ◽  
Empirical Analysis ◽  
Stock Prices ◽  
Efficient Market Hypothesis ◽  
Security Market ◽  
Stock Trading ◽  
Efficient Market ◽  
Basic Framework

The efficient market hypothesis is one of the most important theories in finance. According to this hypothesis, in a stock market with sound laws, good functions, high transparencies, and extensive competitions, all valuable information is timely, accurately, and fully reflected in the trend of stock prices including the current and future values of enterprises. Unless there are market manipulations, it would be impossible for investors to gain more above the average profits in the market by analyzing former prices. Since the efficient market hypothesis has been introduced, it has become an interest in the empirical research of the security market. It is one of the most controversial investment theories and there are many evidences supporting and also opposing this hypothesis. Nevertheless, this hypothesis still holds an important status in the basic framework of mainstream theories in modern financial markets. By analyzing simulated investment transactions in regard to stock trading of three different enterprises, this paper verified that the efficient market hypothesis is partially valid.

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