Model Uncertainty, Limited Market Participation, and Asset Prices

We demonstrate that limited participation can arise endogenouslyin the presence of model uncertainty and heterogeneous uncertainty-averseinvestors. When uncertainty dispersion among investors is small,full participation prevails in equilibrium. Equity premium isrelated to the average uncertainty among investors and a conglomeratetrades at a price equal to the sum of its single-segment components.When uncertainty dispersion is large, investors with high uncertaintychoose not to participate in the stock market, resulting inlimited market participation. When limited participation occurs,participation rate and equity premium can decrease in uncertaintydispersion and a conglomerate trades at a discount.     

The Pricing of Event Risks with Parameter Uncertainty

Financial instruments whose payoffs are linked to exogenous events, such as the occurrence of a natural catastrophe or an unusual weather pattern depend crucially on actuarial models for determining event (e.g., default) probabilities. In many instances, investors appear to receive premiums far in excess of these modeled actuarial probabilities, even for event risks that are uncorrelated with returns on other financial assets. Some have attributed these larger spreads to uncertainty in the probabilities generated by the models. We provide a simple model of such parameter uncertainty and demonstrate how it affects rational investors' demand for event risk exposures. We show that while parameter uncertainty does indeed affect bond spreads, it does not tend to increase spreads by much. Indeed, the spread increases due to parameter uncertainty in our numerical examples are on the order of only 1–2 basis points. Moreover, in many instances, including those that have the most sensible correlation settings, parameter uncertainty tends to decrease the size of bond spreads. We therefore argue that parameter uncertainty does not appear to be a satisfactory explanation for high event-risk returns.     

Stock return predictability and model uncertainty

We use Bayesian model averaging to analyze the sample evidence on return predictability in the presence of model uncertainty. The analysis reveals in-sample and out-of-sample predictability, and shows that the out-of-sample performance of the Bayesian approach is superior to that of model selection criteria. We find that term and market premia are robust predictors. Moreover, small-cap value stocks appear more predictable than large-cap growth stocks. We also investigate the implications of model uncertainty from investment management perspectives. We show that model uncertainty is more important than estimation risk, and investors who discard model uncertainty face large utility losses.     

On the characteristics and performance of long-short, market-neutral and bear mutual funds

We evaluate the return performance of long-short, market-neutral and bear mutual funds using multi-factor models and a conditional CAPM that allows for time-varying risk. Differences in the bearish posture of these mutual funds result in different performance characteristics. Returns to long-short mutual funds vary with the market, returns to market-neutral mutual funds are uncorrelated with the market and returns to bear mutual funds are negatively correlated. Using the conditional CAPM we document significant changes in the market-risk exposure of the most bearish of these funds during different economic climates. We then assess the flow-performance relationship for up to 60 months following up and down markets and find that investors direct flows towards market-neutral and bearish funds for several months after down markets. Market-neutral funds provide a down market hedge, but bear funds do not generate the returns that investors hope for.     

Investing for the Long Run when Returns Are Predictable

We examine how the evidence of predictability in asset returns affects optimal portfolio choice for investors with long horizons. Particular attention is paid to estimation risk, or uncertainty about the true values of model parameters. We find that even after incorporating parameter uncertainty, there is enough predictability in returns to make investors allocate substantially more to stocks, the longer their horizon. Moreover, the weak statistical significance of the evidence for predictability makes it important to take estimation risk into account; a long-horizon investor who ignores it may overallocate to stocks by a sizeable amount.     

Market ambiguity and individual investor information demand

We examine whether ambiguity in the market leads to an increase in information demand by individual investors. Drawing on the asset-pricing model proposed by Mele and Sangiorgi (2015), which incorporates market ambiguity, we measure individual information demand using daily Google searches and measure market ambiguity using a metric based on the market trades of institutional investors. We find that individual investors increase their information demand during periods of greater market ambiguity. We also provide evidence that information demand from individual investors spikes around earnings announcement days primarily when market uncertainty is driven by net-selling activity. Overall, these results suggest that the disagreement among institutional investors either represents uncertainty or contributes to the uncertainty related to a stock, leading to increased demand for information from individual investors.     

Accounting information,disclosure, and expected utility: Do investors really abhor uncertainty?

Investors are said to “abhor uncertainty,” but if there were no uncertainty they could earn only the risk‐free rate. A fundamental result in the analytical accounting literature shows that investors buying into a CARA‐normal CAPM market pay lower asset prices, gain higher ex‐ante expected returns, and obtain higher expected utility, when the market payoff has higher variance. New investors obtain similar “welfare” gains from risk under a log/power utility CAPM. These results do not imply that investors “abhor information.” To realize investors' ex‐ante expectations, the subjective probability distributions representing market expectations must be accurate. Greater payoff risk can add to investors' expected utility, but higher ex‐post(realized) utility comes from better information and more accurate ex‐ante expectations. An important implication for accounting is that greater disclosure can have the simultaneous effects of (i) exposing more fully or perceptibly firms' payoff uncertainty, thereby increasing new investors' expected utility, and (ii) improving market estimates of firms' payoff parameters (means, variances, covariances), thereby giving investors a better chance of realizing their expectations. Paradoxically, better information can be valuable to new investors by exposing more fully and more accurately the risk in firms' business operations and results–new investors maximizing expected utility want both more risk and better information.     

Inconsistent Signals,Earnings Announcements,and Market Uncertainty

We test the proposition in Johnstone (2016) that new information may lead to higher, rather than lower, uncertainty about firms’ future payoffs. Based on the Bayesian rule, we hypothesize earnings news that is inconsistent with investors’ prior belief will lead to higher market uncertainty. Using earnings signals in the past few quarters to proxy for investors’ prior belief, we find supporting evidence that, relative to consistent earnings news, inconsistent news results in an increase in market uncertainty measured by implied volatility. Inconsistent earnings news has a larger effect on market uncertainty when prior beliefs are stronger and when the news is negative. Overall, our evidence highlights the importance of prior belief and inconsistent signals in understanding the effect of earnings news on market uncertainty.     

金融创新、投资者逃离与央行危机救助

从1970年的商业票据危机到2008年的全球金融危机,历史上发生过多次因金融创新的复杂性诱发投资者逃离进而演化为金融危机的事件,而危机的最终化解多借助于央行的危机救助。本文基于投资者逃离模型,从金融创新及其产生的投资者不确定性出发讨论金融危机中投资者逃离行为,并通过对投资者逃离行为的分析探讨央行危机救助的时点与方式。本文认为,就金融危机的事前预防而言,央行应在创新工具运用的过程中引导金融机构开展充分的投资者教育及对创新工具的总规模进行适当限制从而降低危机发生的概率和破坏性;就金融危机的事后救助而言,央行危机救助的时点应放在投资者对未来的不确定性突然增加并开始调整原有策略的时刻,救助的主要措施是承诺在一定条件下购买资产或注入流动性,从而降低投资者不确定性,促使投资者改变逃离市场的策略或者至少避免投资者逃离成为群体行为。     

Can earnings fixated investors survive in a competitive securities market? Implications for sustained price anomalies and mark-to-market accounting

We model the dynamic survival of earnings fixated investors in a competitive securities market that allows for learning and arbitrage and that is populated by heterogeneous investors. Our model is distinct from those based on aggressive trading by overconfident investors. We prove that in the absence of noise traders, rational investors will drive out earnings fixated investors from the market in the long-run. More interestingly, we show that in a market with noise traders, some proportion of earnings fixated investors survive in long-run equilibrium for all feasible model parameter values. Furthermore, under no circumstances can the earnings fixated investors be driven out of the market completely. On the contrary, for some parameter values, the earnings fixated investors drive out the rational investors entirely. These results rationalize the long-run sustainability of common pricing anomalies. They also highlight potential benefits to society of mark-to-market accounting.     

Systemic Risk and International Portfolio Choice

Returns on international equities are characterized by jumps; moreover, these jumps tend to occur at the same time across countries leading to systemic risk. We capture these stylized facts using a multivariate system of jump‐diffusion processes where the arrival of jumps is simultaneous across assets. We then determine an investor's optimal portfolio for this model of returns. Systemic risk has two effects: One, it reduces the gains from diversification and two, it penalizes investors for holding levered positions. We find that the loss resulting from diminished diversification is small, while that from holding very highly levered positions is large.     

Pricing,issuance volume,and design of innovative securities: The role of investor information

This study investigates the role of asymmetric information for the pricing, issuance volume, and design of innovative securities. By analyzing the information that structured product issuers provide to the investors of those products, we can identify specific sources of asymmetric information between the issuers and investors in this market. We show that issuers exploit this information friction to offer products to investors that appear more profitable for the issuer. In addition, we find that the friction induces issuers to design products with higher information asymmetry. Our results suggest that product issuers’ behavior increases information frictions in the financial system.     

Allocation to Anchor Investors,Underpricing, and the After‐Market Performance of IPOs

We study bidding by anchor investors in a two‐stage initial public offering (IPO) process and document a negative, causal relation between allocation to anchor investors and underpricing. We find that anchor investors are likely to invest in hard‐to‐place offerings characterized by valuation uncertainty. We also document a positive relation between allocation to reputed anchor investors and returns up to lock‐up expiration. Our evidence provides support for information revelation and targeting specific investors’ theories of book building. Anchor‐backed IPOs earn superior returns mainly due to monitoring. Who bids in an IPO seems to matter just as particular types of bids do.     

Explaining share price disparity with parameter uncertainty: Evidence from Chinese A- and H-shares

The price disparity between the A- and H-share markets for dual-listed firms in China is one of the most intriguing puzzles in the Mainland and Hong Kong financial markets. In this paper, we revisit this price disparity puzzle using the channel of parameter uncertainty. In the presence of information asymmetry and market segmentation, investors have different views on a firm’s asset volatility, and hence different valuations of the same reference firm. We estimate a structural model for equity pricing using a Bayesian approach, in which the uncertainty of investor model parameters is represented by the posterior standard deviation of the firm’s asset volatility. Our regression analysis shows that in addition to other market-based and macro factors, parameter uncertainty explains variations in price disparity.     

Loss aversion,asymmetric market comovements,and the home bias

Loss aversion has been used to explain why a high equity premium might be consistent with plausible levels of risk aversion. The intuition is that the first-order-different utility impact of wealth gains and losses leads loss-averse investors to behave similarly to investors with high risk aversion. But if so, should those agents not perceive larger gains from international diversification than standard expected-utility investors with plausible levels of risk aversion? They might not, because comovements in international stock markets are asymmetric: correlations are higher in market downturns than in upturns. This asymmetry dampens the gains from diversification relatively more for loss-averse investors. We analyze the portfolio problem of such an investor who has to choose between home and foreign equities in the presence of asymmetric comovement in returns. Perhaps surprisingly, in the context of the home bias puzzle we find that loss-averse investors behave similarly to those with standard expected-utility preferences and plausible levels of risk aversion. We argue that preference specifications that appear to perform well with respect to the equity premium puzzle should be subjected to this “test”.     

How do investors react under uncertainty?

It has long been accepted that risk plays an important role in determining valuation where risk reflects that investors are unsure of future returns but are able to express their prior expectations by a probability distribution of these returns. Knight (1921) introduced the concept of uncertainty where investors possess incomplete knowledge about this distribution and so are unable to formulate priors over all possible outcomes. One common approach for making uncertainty tractable is to assume that investors faced with uncertainty will base their decisions on the worst case scenario (i.e. follow maxmin expected utility). As a consequence it is postulated that investors will become more pessimistic as uncertainty increases, upgrading bad news and downgrading good news. Using Australian data, we find evidence that investors react to bad news at times of high market uncertainty but largely ignore good news which is consistent with them taking on a pessimistic bias. However, we also find evidence of the reverse when market uncertainty is low with investors taking on an optimistic stance by ignoring bad news but reacting to good news. We also find that the impact that market uncertainty has on the reaction of investors to new information is modified by the prevailing market sentiment at the time of the announcement. Besides throwing light on the question of how uncertainty impacts on investor behaviour, our findings seriously challenge the common assumption made that investors consistently deal with uncertainty by applying maxmin expected utility.     

Structural breaks, parameter uncertainty, and term structure puzzles

We show that uncertainty about parameters of the short rate model can account for the rejections of the expectations hypothesis for the term structure of interest rates. We assume that agents employ Bayes rule to learn parameter values in the context of a model that is subject to stochastic structural breaks. We show that parameter uncertainty also implies that the verdict on the expectations hypothesis varies systematically with the term of the long bond and the particular test employed, in the same way that is found in empirical tests.     

THE DAYLIGHT SAVING TIME ANOMALY IN STOCK RETURNS: FACT OR FICTION?

Stock market returns in 22 markets around the world show no evidence of a daylight saving time effect. Returns on the days following a switch from or to daylight saving time do not behave any differently from stock market returns on any other day of the week or month. These results reject earlier conclusions in the literature—based on less data—that investors’ mood changes induced by changes in sleep patterns significantly affect stock returns.     

Who,if anyone,reacts to accrual information?

We show that the vast majority of investors ignore value-relevant accruals information when it is first released, but that investors who initiate trades of at least 5,000 shares tend to transact in the proper direction. These investors trade on accruals information only when the previously-announced earnings signal is non-negative. Unconditionally, those investors initiating the smallest trades appear to respond to accruals in the wrong direction, but further investigation suggests this behavior is explained by their attraction to attention-grabbing stocks. Finally, we find that those who trade on accruals information have insufficient market power to mitigate the accruals anomaly.     

投资银行-机构投资者关系、“捧场”与IPO中的利益问题

投资银行是直接融资过程中最重要的中介机构,作为融资产品的“卖方”代表,其核心竞争力源于它所构建的投资者关系网络,但现有文献对于投行-投资者关系在证券发行中的作用还缺乏系统的实证研究。本文利用机构投资者在中国IPO新股发行中的完整询价记录,基于报价参与和报价水平两个维度提出了一种新的动态关系强度测算方法,并由此细致刻画了投行-机构关系对股票发行、定价的作用机制。结果发现:(1)投行可以驱动关系机构主动认购其承销的IPO新股,并引导关系机构给出与投行估值水平保持一致的高位报价,进而有效缓解了IPO拍卖制下的“投资者参与不确定性问题”。(2)关系机构的捧场报价显著提高了股票发行价格、增加了投行的承销收入;但是当新股交易价格在长期内逐渐向其内在价值水平收敛时,受到关系机构捧场支持越多的IPO新股,其长期回报率相对越低。(3)投行与机构的关系在本质上是互惠的,一旦投行被赋予新股分配权力,它明显倾向于将新股抑价发行带来的巨大利益分配给在前期捧场的关系机构,二者的关系越强,机构报价被认定为“有效报价”的概率越高,而一旦被认定为有效报价,关系机构的新股需求更是将被优先满足。