Testing commodity futures market efficiency under time-varying risk premiums and heteroscedastic prices

We propose a novel test to measure market efficiency while estimating the time-varying risk premiums of commodity futures, given that the prices are heteroscedastic. The risk premium is estimated using a state-space model with a Kalman filter modified for heteroscedasticity. Using 79 commodity futures traded on 16 exchanges during the period 2000–2014 and a Monte Carlo simulation, we demonstrate that the proposal produces robust results compared with conventional approaches. The global financial crisis has improved the efficiency and affected the trading volumes of commodity futures, but it has had no effect on the average or the volatility of risk premiums.     

工业体系和民营企业兴起——基于252家中国最大民营制造业企业的经验研究

主流经济学家把改革开放后民营企业的大规模兴起，主要归因为市场经济条件下发挥企业家精神和遵循比较优势的必然结果。但是这无法解释为什么民营企业在兴起之初就广泛和快速地进入到各个工业，尤其是技术和资本密集型工业。基于中国工业史和252家中国最大民营制造业企业创业发展史的历史证据，文章找回"工业体系"这一被主流所忽略的重大历史现象和学术概念，从而首次提出一种理解中国民营企业发展独特性的结构性解释。文章发现：从计划经济时期继承而来的门类齐全和独立完整的工业体系，是解释民营企业创业和发展独特性的关键变量；已有的由国有企业和科研院所组成的工业体系，从市场机会、技术能力和组织资源等方面塑造了民营企业的创业选择和发展路径。所以，中国民营企业的快速发展不是仅凭自由市场就会自动出现的普遍现象，而是在市场条件下充分利用工业体系提供的技术和市场条件才得以出现的特殊现象。     

Net neutrality and market power: The case of South Africa

Net neutrality rules have been implemented in many developed countries, often in response to concerns over network operator market power and potential blocking or throttling of content. However, developing countries typically have significantly lower levels of internet penetration and usage. Market power in respect of internet access looks quite different given that mobile is the predominant means of connection and there are often three or more mobile operators. In South Africa, there is a quasi-monopoly in the paid satellite broadcasting market and broadband providers zero-rating content from third parties (such as Netflix) may bring about more competition. We test the main theories of harm arising in the net neutrality debate, including network operator market power and exclusion among content providers using data on the number of announced prefixes and peers and IP addresses and considering examples of bundling and zero-rating conduct by operators. We find that net neutrality rules are less likely to be required in South Africa and other developing countries and that strict enforcement of such rules could in fact hinder competition in markets for content, telecommunications networks and other related markets.     

金融创新如何缓解信任品市场失灵?——中国食品安全责任强制保险的自然实验

信任品市场(如食品、医药等)存在的问题一直困扰着中国和世界很多国家。关于产品和服务质量的信息不对称(道德风险和逆向选择)会导致信任品市场失灵。缓解信任品市场失灵,一种常见的解决方案是政府监管;而经济学家认为更加基于市场的解决方案(例如强制责任保险等金融创新)可能更为有效。在理论上,强制责任保险有两种相反的效应:保险公司的监督减少了道德风险 vs. 保险加剧了企业的道德风险,但一直亟待实证检验。幸运的是,中国食品安全责任强制保险的改革实验走在了世界的前列。本文利用了中国在不同地区、不同时间推行的这个自然实验,通过双重差分的方法识别出责任保险对于信任品市场的因果效应。本文的研究发现,强制责任保险能显著降低食品安全事故发生概率。这表明政府强制推行的金融创新可以成为信任品市场失灵的一种有效的替代性解决方案。     

研发市场界定的适用困境及应对策略

研发市场是经营者在特定产品和技术竞争中形成的市场范围。由于研发活动的不确定性，反垄断执法机关在界定研发市场时难以准确厘定市场边界，更深层次的原因在于维持竞争与激励研发的关系尚不明晰。研发竞争中的垄断行为难以通过相关市场界定的方式判断其违法性，需要结合具体案情和市场条件，动态分析涉案行为是否损害产品或技术研发竞争。     

Exploring how innovation strategies at time of crisis influence performance: a cluster analysis perspective

This paper analyzes the connection between innovation activities of companies – implemented before crisis – and their performance – measured at time of crisis. The companies listed in the STAR Market Segment of the Italian Stock Exchange are analyzed. Innovation is measured through the level of investments in total tangible and intangible fixed assets in 2006–2007, while performance is captured through growth – expressed by variations of sales, total assets and employees – profitability – through ROI or ROS – and productivity – through asset turnover or sales per employee in the period 2008–2010. The variables of interest are analyzed and compared through statistical techniques and by adopting cluster analysis. In particular, a Voronoi tessellation is also implemented in a varying centroids framework. In accord with a large part of the literature, we find that the behaviour of the performance of the companies is not univocal when they innovate.     

Adaptive market hypothesis: The story of the stock markets and COVID-19 pandemic

Since the level of markets’ information efficiency is key to profiteering by strategic players, Shocks; such as the COVID-19 pandemic, can play a role in the nature of markets’ information efficiency. The martingale difference and conditional heteroscedasticity tests are used to evaluate the Adaptive form of market efficiency for four (4) major stock market indexes in the top four affected economies during the COVID-19 pandemic (USA, Brazil, India, and Russia). Generally, based on the martingale difference spectral test, there is no evidence of a substantial change in the levels of market efficiency for the US and Brazilian stock markets in the short, medium, and long term. However, in the long term, the Indian stock markets became more information inefficient after the coronavirus outbreak while the Russian stock markets become more information efficient. Intuitively, these affect the forecastability and predictability of these markets’ prices and/or returns. Thereby, informing the strategic and trading actions of stock investors (including arbitrageurs) towards profit optimization, portfolio asset selection, portfolio asset adjustment, etc. Similar policy implications are further discussed.     

Assessing the reversal of investor sentiment

Assessing the reversal of sentiment in stock markets is needed because, according to the social mood cycle, the change of social mood over time is an antecedent of price movements. The purpose of this study is to empirically assess reversal of investor sentiment, to show the phases of social mood cycle from increasing mood to decreasing mood, and to explain the dynamic change in market inefficiency from increasing to decreasing. Growth modeling, developed particularly for dealing with the change over time, is used in this study for assessing the reversal of investor sentiment. The autocovariance structure of errors and the variances/covariances of the random coefficients are all taken into account in the model. The results have indicated that the change in investor sentiment over time is inverted U-shaped for the entire market. Moreover, arbitrage constraint and stock characteristics exert a joint moderating effect on sentiment reversal. Less arbitrage constraint can strengthen sentiment reversal only when the market for individual stocks is dominated by noise traders. Based on the results obtained, we discuss asset pricing, liquidity management, and market intervention.     

资本市场开放与股权资本成本——基于沪港通、深港通的实证研究

本文基于沪港通和深港通研究资本市场开放对中国内地股权资本成本的影响。研究发现,受政策风险和市场环境等因素所限,沪港通在初始阶段并未对沪市公司的股权资本成本产生显著影响,但随着政策进一步完善、市场逐渐稳定和交易不断活跃,其对股权资本成本的降低效果于实施两年后开始显现;深港通建立在沪港通的制度基础和运行经验上,其在开通后显著降低了标的公司的股权资本成本。本文还进一步分析了资本市场开放影响股权资本成本的竞争渠道和信息渠道,发现深港通对股权资本成本的降低作用主要集中在投资者竞争程度较高,或是公开信息质量较高、信息不对称程度较低的股票样本。     

Spillovers between sovereign CDS and exchange rate markets: The role of market fear

As important variables in financial market, sovereign credit default swaps (CDS) and exchange rate have correlations and spillovers. And the volatility spillovers between the two markets become further complicated with the effect of market fear caused by extreme events such as global pandemic. This paper attempts to explore the complex interactions within the “sovereign CDS-exchange rate” system by adopting the forecast error variance decomposition method. The results show that there is a relatively close linkage between the two markets and the total spillover index of the system is dynamic. For most of the past, the exchange rate has a higher spillover effect on the sovereign CDS than vice versa. Moreover, after the market fear variables are introduced, the “sovereign CDS-exchange rate” system and market fear variables present bidirectional spillovers. The results of the study have particular significance for maintaining the financial stability and preventing risk contagion between markets.