农民工市场失灵及其矫正

农民工短缺现象的出现至少在一定程度上说明了农民工市场失灵,难以依靠市场自身的力量调节供求关系。市场失灵不仅造成用工短缺,也使社会福利受损。农民工市场失灵,除了不完全竞争、信息不完全等一般因素外,还与该市场发育不成熟、制度安排不合理密不可分。近年来一系列有关农民工政策的出台,在一定程度上可使失灵的市场得到矫正。     

新冠肺炎疫情的经济影响分析：长期视角与短期应对*

本文从需求和供给两侧分析了此次新冠疫情对我国经济的短期和长期影响。在需求侧，基于理论分析和非典疫情对经济的影响特征，经济总需求会随着此次疫情的结束而在短期内快速得到恢复。但此次疫情也会加大总需求和居民收入增速的下行压力。在供给侧，疫情不仅会降低劳动力资源配置效率，加剧劳动力供需结构矛盾，同时也大幅降低了我国的资本投资，在缺乏有效干预措施下，很可能加剧我国资本投资和经济总体增速的短期下滑趋势。而基于理论分析，相应供给冲击也将对我国长期产出带来增长压力。基于疫情对我国经济需求侧和供给侧的影响分析，2020年要实现全面建成小康社会的经济目标需要实施改革力度更大、更为有效的财政和货币等支持政策。     

Earnings Announcements: Good News for Institutional Investors and Short Sellers

In this paper, we consider the trading behavior of institutional investors and short sellers around earnings announcements. The results suggest that institutional investors, and to a lesser extent short sellers, successfully anticipate earnings news. In the period immediately after the earnings announcement, both types of traders are active in the market and trade in response to the earnings announcement. In particular, short sellers are quick to increase their short positions when a company releases bad news. Institutional traders also trade in response to the news; however, they take longer to react.     

Short Sale Constraints and Dispersion of Opinion: Evidence from the Indian Equity Market

Short sale constraints can inflate market prices, as bearish investors cannot act on their market views. The paper uses data from the Indian equity market to test whether opinion dispersion leads to higher overpricing when short sales are prohibited. The Indian equity market provides a natural testing environment, as short sales were banned between 2001 and 2008. The empirical results offer supportive evidence of the relation between opinion dispersion and overpricing in a market with short sale constraints.     

PRICING AND HEDGING SHORT STERLING OPTIONS USING NEURAL NETWORKS

This paper compares the performance of artificial neural networks (ANNs) with that of the modified Black model in both pricing and hedging short sterling options. Using high‐frequency data, standard and hybrid ANNs are trained to generate option prices. The hybrid ANN is significantly superior to both the modified Black model and the standard ANN in pricing call and put options. Hedge ratios for hedging short sterling options positions using short sterling futures are produced using the standard and hybrid ANN pricing models, the modified Black model, and also standard and hybrid ANNs trained directly on the hedge ratios. The performance of hedge ratios from ANNs directly trained on actual hedge ratios is significantly superior to those based on a pricing model, and to the modified Black model. Copyright © 2012 John Wiley & Sons, Ltd.     

一种井口压装防喷装置的设计

一种井口压装防喷装置,在井口压裂过程中,用于投放油管堵塞器以堵住油管,防止井喷。其结构包括上下旋塞阀和升高短节。当钻井产生井喷时,保证旋塞阀的上下两端压力平衡,使旋塞阀可以轻松打开,升高短节内的油管堵塞器即能自动下降密封。     

浅谈中国概念股的信任危机

近年来,美国做空机构做空中国概念股的现象频频出现。文中基于浑水公司和香橼公司能够不断做空中国概念股的案例,对做空公司的发展,中国概念股的现状以及做空原因等进行分析,并辩证地看待做空机构的存在对资本市场发展的意义,同时对中国概念股如何应对做空机构,在危机中生存提出建议。     

Exploring the predictability of range‐based volatility estimators using recurrent neural networks

We investigate the predictability of several range‐based stock volatility estimates and compare them with the standard close‐to‐close estimate, which is most commonly acknowledged as the volatility. The patterns of volatility changes are analysed using long short‐term memory recurrent neural networks, which are a state‐of‐the‐art method of sequence learning. We implement the analysis on all current constituents of the Dow Jones Industrial Average index and report averaged evaluation results. We find that the direction of changes in the values of range‐based estimates are more predictable than that of the estimate from daily closing values only.     

Investment Horizon and Repo in the Over‐the‐Counter Market

This paper presents a three‐period model featuring a short‐term investor in the over‐the‐counter bond market. A short‐term investor stores cash because of a need to pay cash at some future date. If a short‐term investor buys bonds, then a deadline for retrieving cash lowers the resale price of bonds for the investor through bilateral bargaining in the bond market. Ex‐ante, this hold‐up problem explains the use of a repo by a short‐term investor, the existence of a haircut, and the vulnerability of a repo market to counterparty risk. This result holds without any uncertainty about bond returns or asymmetric information.