The aggregate and sectoral time‑varying market efficiency during crisis periods in Turkey:a comparative analysis with COVID‑19 outbreak and the global financial crisis

This study aims to examine the time-varying efficiency of the Turkish stock market’s major stock index and eight sectoral indices,including the industrial,financial,service,information technology,basic metals,tourism,real estate investment,and chemical petrol plastic,during the COVID-19 outbreak and the global financial crisis(GFC)within the framework of the adaptive market hypothesis.This study employs multifractal detrended fluctuation analysis to illustrate these sectors’multifractality and short-and long-term dependence.The results show that all sectoral returns have greater persis-tence during the COVID-19 outbreak than during the GFC.Second,the real estate and information technology industries had the lowest levels of efficiency during the GFC and the COVID-19 outbreak.Lastly,the fat-tailed distribution has a greater effect on multifractality in these industries.Our results validate the conclusions of the adaptive market hypothesis,according to which arbitrage opportunities vary over time,and contribute to policy formulation for future outbreak-induced economic crises.

Cryptocurrencies,gold,and WTI crude oil market efficiency:a dynamic analysis based on the adaptive market hypothesis

This study examined the evolving oil market efficiency by applying daily historical data to the three benchmark cryptocurrencies(Bitcoin,Ethereum,and Ripple),gold,and West Texas Intermediate(WTI)crude oil.The data coverage of daily returns was from August 2015 to April 2019.We applied two alternative tests to examine linear and nonlinear dependency,i.e.,automatic portmanteau and generalized spectral tests.The analysis of observed results validated the adaptive market hypothesis(AMH)in all markets,but the degree of adaptability between the data was different.In this study,we also analyzed the existence of evolutionary behavior in the market.To achieve this goal,we checked the results by applying the rolling-window method with three different window lengths(50,100,and 150 days)on the test statistics,which was consistent with the findings of AMH.

Expand Trade to Adapt to Market Competition——China National Machinery Import & Export Corporation

Founded in 1950, the China National Machinery Import & Export Corporation (CMC) is a large national foreign trade enterprise directly under the administration of the Ministry of Foreign Trade and Economic Cooperation, specializing in the import and export of electromechanical products. It is one of our country’s first and largest foreign trade corporations. Since its founding 45 years ago, the corporation has been consistently endeavoring to develop and expand foreign trade in electromechanical products, and

Decision-making under Market Indeterminacy

The Efficient Markets Hypothesis(EMH)is the focusing topic in the past 50 years of financial market researches.Many empirical studies are then provided that want to test EMH but have no consensus.The perception of EMH determines the attitude and strategy of participants and regulators in financial market.One perception of EMH argues that investors’behavior of seeking abnormal profits and arbitrage drives prices to their“correct”value.Investigating the“correct”value derives the concept of“market indeterminacy”.It means the inability to determine whether stock prices are efficient or inefficient.Market indeterminacy pervades stock markets because“correct”prices are unknown because of imperfect information and model sensitivity.Market indeterminacy makes arbitrage risky and makes event studies unreliable in some policy and litigation applications.The concept of market efficiency is needed to be re-recognized considering the mechanism of price formation.In order to further research and practice in law and financial market,there needs a view from the“jumping together”of disparate disciplines.Adaptive Markets Hypothesis(AMH)that using the evolutionary principles in financial market is a new viewpoint on cognitive decision and deserves to be paid more attention to.