私有信息、评级偏差和中国评级机构的市场声誉

考虑到评级机构拥有市场声誉的本质在于其可以通过扭曲评级从而对市场产生影响,本文分两步研究中国发行人付费评级机构的市场声誉:第一步,将信用评级对各种基本面因素进行回归,并以实际评级与回归预测值的差值作为评级偏差的量度。与既有文献相比,本文的重要改进是在基本面因素中引入了发债企业与各评级机构(分支机构)最短距离的均值和方差,这能较好地控制因发债企业私有信息可能造成的选择偏误。第二步,考察评级偏差和机构特征如何影响企业的发债成本。研究表明,中国评级机构作为一个整体具有显著的市场声誉,但各评级机构之间存在很大的差异性。最后,考虑到评级机构与发债企业在选址上可能会有集聚效应,我们基于高铁开通事件进行双重差分检验,研究表明本文结论是稳健的。     

“过度反应“和“反应不足“现象的理性解释——股票市场中知情机构投资者的交易行为研究

有效市场假说不能很好地解释“过度反应”和“反应不足”现象,原因在于“信息无成本获得”基本假设过强。如果放松这一假设,理性的知情机构投资者为获得合法“私有信息”需要付出固定成本,为了弥补该成本,必须通过“本量利分析”制定“保本点”持仓量,并用策略性交易来掩饰真实意图。因此股票价格对于私有信息的反应肯定是“过度反应”和“反应不足”的;而股票价格对于公开信息的反应,则要取决于理性的知情机构投资者理性的持仓量是否达到“保本点”。     

私有信息影响我国股票市场价格波动的实证研究

本文针对中国股票市场的特殊情况,改进了波动性模型和隐藏性假说模型,利用中国股票市场的日内交易高频数据实证检验了私有信息对股票市场价格波动的影响。研究发现:私有信息确实存在并对我国股票市场日内交易价格收益率的波动产生了显著性的影响,主要表现为知情交易者为了获得最大的收益,采用了特定的交易类型来避免信息的过快泄露,从而使得市场中的价格变动比率与成交量占比不成比例。     

共同机构投资者对企业关联交易的影响：监督还是合谋

利用关联交易侵占中小投资者权益是大股东掏空企业的主要手段,而共同机构投资者是否与大股东合谋参与此类关联交易目前尚无定论。基于此,本文通过2007—2021年我国A股上市企业数据,考察了共同机构投资者对企业关联交易的影响。研究发现：共同机构投资者在企业关联交易中扮演了监督者的角色,参股企业后显著降低了关联交易规模;共同机构投资者主要通过降低企业第二类代理成本、提升企业信息透明度等渠道抑制关联交易行为,从而提高收益和降低风险。此外,当企业所在地区法治水平低时,共同机构投资者会更努力扮演好监督者的角色。本文不仅揭示了共同机构投资者与企业关联交易之间的作用机制,也为我国规范和治理企业关联交易提供了新思路。     

公共信息、私有信息：公众更看重哪一个——针对私有信息定价效率的实证研究

本文以2003--2008年深圳证券交易所主板市场的上市公司为样本,考察了投资者为获得信息所支付的溢价与信息结构之间的关系,由此判断投资者对公开信息和私有信息的不同关注度。研究显示,投资者支付的信息溢价与信息结构的关系为非线性。当私有信息占比较低时,投资者支付的信息溢价与信息结构呈现正相关;随着私有信息占比的提高,投资者支付的信息溢价与信息结构呈现负相关关系。就中国股票市场整体而言,信息披露的混同均衡状态强于分离均衡状态。     

机构投资者共同持股与内部人交易收益

本文基于2010-2020年中国A股上市公司数据,实证考察机构投资者共同持股对内部人交易收益的影响及其作用机制。研究发现,机构投资者共同持股可以通过降低企业内部人员信息优势、强化外部监督以及降低股价波动风险对企业内部人交易行为产生治理作用。进一步研究表明,在信息不对称程度较高、投资者关注度较低以及内部人持股比例较高的企业当中,机构投资者共同持股对内部人交易收益的抑制作用更强。     

信息不对称和报酬方案对预算松弛的影响研究

本文用实验方法研究预算的激励功能和计划功能需要同时发挥时,在预算参与的情况下,信息不对称和报酬方案对预算松弛的影响。本文的研究发现,信息不对称和报酬方案都会影响预算松弛:无论是否存在信息不对称,编制松弛在真实诱导报酬方案下要低于松弛诱导报酬方案;无论是否存在信息不对称,真实诱导报酬方案下的业绩要好于松弛诱导报酬方案下的业绩;信息不对称时不同诱导报酬方案下的业绩差异大于没有信息不对称时不同诱导报酬方案下的业绩差异;无论是否存在信息不对称,松弛诱导报酬方案下的报酬要大于真实诱导报酬方案下的报酬。上述结果表明,必须以系统思维来进行预算管理,将预算管理置于整个管理体系中考虑,做到与管理体系中的其他内容协调配套,只有这样才能充分发挥预算管理的功能。     

中国A股市场上的机构投资者是理性的吗——基于知情交易视角的分析

本文利用2000~2014年沪深两市A股一般上市公司季度数据,研究机构投资者知情交易与特征组合相对超额收益的关系。实证结果显示:第一,当机构投资者知情交易变大时,持有盈余价格比高、利润总额同比增长率高、账面市值比低、价格高、规模大的股票的当期相对超额收益变大,知情机构投资者是理性的。第二,当机构投资者知情交易变大时,持有股息率低、盈余价格比低、利润总额同比增长率低、账面市值比低、价格低、规模小的股票的未来相对超额收益变大,知情机构投资者是非理性的。知情机构投资者并非是完全理性的,由于其更关注当期利益,而忽略长期价值投资,不利于维护股市的稳定。     

Price discovery in the U.S. stock and stock options markets: A portfolio approach

Option prices vary with not only the underlying asset price, but also volatilities and higher moments. In this paper, we use a portfolio of options to seclude the value change of the portfolio from the impact of volatility and higher moments. We apply this portfolio approach to the price discovery analysis in the U.S. stock and stock options markets. We find that the price discovery on the directional movement of the stock price mainly occurs in the stock market, more so now than before as an increasing proportion of options market makers adopt automated quoting algorithms. Nevertheless, the options market becomes more informative during periods of significant options trading activities. The informativeness of the options quotes increases further when the options trading activity generates net sell or buy pressure on the underlying stock price, even more so when the pressure is consistent with deviations between the stock and the options market quotes. JEL Classification C52, G10, G13, G14     

Stock Price Behavior over Trading and Non-trading Periods: Evidence from the Taiwan Stock Exchange

This paper examines the stock price behavior in the trading and non-trading periods for stocks listed on the Taiwan Stock Exchange over 1971-96. The results indicate that the trading-time return variances are higher than the non-trading-time return variances especially for the larger trading-volume quintiles. This result is consistent with the private information hypothesis. Moreover, open-to-open return variances are higher than close-to-close return variances. Since both the opening and the closing transactions are conducted by the call auction procedure, the results are consistent with the trading halt hypothesis but not with the trading mechanism hypothesis.     

Opinion Divergence Among Professional Investment Managers

Abstract:  We find that opinion divergence among professional investment managers is commonplace, using a large sample of transaction-level institutional trading data. When managers trade together, future returns are similar regardless if they are all buying or selling, inconsistent with the notion that professional investment managers possess stock picking ability or private information that is of investment value. However, when managers trade against each other, subsequent returns are low, especially for stocks that are difficult to short. This U-shaped disagreement-return relationship is consistent with Miller's (1977) hypothesis that, in the presence of short-sale constraints, opinion divergence can cause an upward bias in prices.     

Communication in Private-Information Models: Theory and Computation

Communication and no-communication versions of a two-stage principal-agent model are compared. The models contain a risk-averse agent and two sources of private information, a shock to preferences followed by a productive action. Both models are formulated as linear programs, which are then used to compute solutions to examples. For the communication model, an alternative method of accounting for the utility from off-equilibrium strategies is derived. This method greatly reduces the size of the linear program. For the no-communication model a Revelation-Principle like proof is provided. In simple cases, a sufficient condition for communication to be valuable is derived. In these cases, communication improves risk-sharing in bad states of the world. In more complicated cases, computed examples demonstrate how communication may also alter labor supply. Further examples demonstrate how action and consumption lotteries may separate agents by their shock.     

Corporate Sales, Predisclosure Information and Return Variability

This paper investigates the determinants of return variability between accounting report and non-report periods. A model of information dissemination in financial markets is developed which shows that if corporate sales activity is a source of predisclosure information, the ratio of return variability between accounting report and non-report periods decreases in contribution margin per dollar sales. Greater contribution margin increases that portion of cash flow variability which is predictable by investors' observation of sales activity and, therefore, contribution margin indexes the informativeness of sales-related predisclosure information. Greater informativeness increases return variability in the predisclosure period relative to the accounting report period. Supporting evidence for this prediction is presented.     

中国A股市场大交易量与收益率关系的研究

利用技术分析制定股票投资策略是投资者主要采用的方法之一,而对交易量与收益率两者之间关系的研究又是技术分析的基础。我们认为,大交易量能更好地预测未来股票的收益。本文通过对中国A股市场代表不同规模股票的指数实证研究发现,不同指数在大交易量形成后的检验期里反应是不同的。代表大盘股的指数存在明显的"大交易量溢价效应";而代表小盘股的指数几乎不存在这种效应。我们还进一步的发现,这种"大交易量溢价效应"只发生在指数上涨了10%-20%的情况下。最后,我们给出了相关的投资策略。     

American stochastic volatility call option pricing: A lattice based approach

This study presents a new method of pricing options on assets with stochastic volatility that is lattice based, and can easily accommodate early exercise for American options. Unlike traditional lattice methods, recombination is not a problem in the new model, and it is easily adapted to alternative volatility processes. Approximations are developed for European C.E.V. calls and American stochastic volatility calls. The application of the pricing model to exchange traded calls is also illustrated using a sample of market prices. Modifying the model to price American puts is straightforward, and the approach can easily be extended to other non-recombining lattices.