Speculative Overpricing in Asset Markets With Information Flows

In this paper, we derive and experimentally test a theoretical model of speculation in multiperiod asset markets with public information flows. The speculation arises from the traders' heterogeneous posteriors as they make different inferences from sequences of public information. This leads to overpricing in the sense that price exceeds the most optimistic belief about the real value of the asset. We find evidence of speculative overpricing in both incomplete and complete markets, where the information flow is a gradually revealed sequence of imperfect public signals about the state of the world. We also find evidence of asymmetric price reaction to good news and bad news, another feature of equilibrium price dynamics under our model. Markets with a relaxed short‐sale constraint exhibit less overpricing.     

透明度与市场效率——基于信息不对称的适应性学习研究

通过拓展Pouget模型,考察了当所有投资者采用适应性学习(有限理性)规则更新信念时,订单信息的透明度增加如何影响市场的价格发现效率和福利配置效率.结果表明,透明度增加后,市场效率大幅降低,价格发现和福利配置都难以收敛到理性预期均衡.进一步剖析投资者的策略选择可以发现,透明度增加后,拥有信息优势的知情者倾向于提交对自己更加有利的订单,而放弃均衡的交易策略;非知情者为了规避由此带来的逆向选择风险,也会放弃均衡策略而倾向于提交更加保守的订单,最终导致市场效率大幅下降.     

指令驱动市场中非知情交易者的最优交易策略

在非对称信息下,综合非知情交易者对资产价值的预期、私人估值及资产价值波动,构造指令驱动市场价格形成的动态模型,给出非知情交易者指令提交策略的解析解,并依此描述了非知情交易者对资产价值预期的动态更新过程.研究发现:私人估值和资产价值波动通过影响非知情交易者最优策略,使得市场进入不同均衡状态;在每个均衡状态下,非知情交易者根据资产价值的预期变化更新交易策略,进而引起知情交易者策略调整,特别地,使得知情交易者被挤出市场成为可能.进一步分析表明,私人估值、资产价值波动及知情交易者比例对市场流动性的影响依赖于每个均衡中限价指令执行风险的差异.     

Financial Edgework and the Persistence of Rogue Traders

This work explores financial edgework by professional speculative traders as an explanation for the persistence of rogue trading in financial markets. The article joins in the scholarly application of “edgework,” the social psychological study of voluntary risk, to speculative trading. The discussion focuses on the origins and persistence of that subset of behavior wherein the trader knowingly creates the condition in which he or she endangers the brokerage house that employs them and even, at times, threatens the public's perception of the integrity of the securities industry. Going over the edge between risk taking and unauthorized rogue trading is explained by looking at five inducements to escalate risk taking provided in the securities industry. This examination of financial edgework demonstrates how and, to a lesser degree, why rogue trading is a result of the security industry's pursuit of and desire to capitalize upon yet not publicize an occupational culture stressing a “risk‐and‐win” ethos.     

Keeping up with the Neighbors: Social Interaction in a Market Economy

We consider a world in which individuals have private endowments and trade in markets while their utility is negatively affected by the consumption of their neighbors. Our interest is in understanding how the social structure of comparisons, taken together with the familiar fundamentals of the economy (endowments, technology, and preferences), shapes equilibrium prices, allocations, and welfare. We show that equilibrium prices and consumption are a function of a single network statistic: centrality. An individual's “centrality” is given by the weighted sum of paths of different lengths to all others in a social network. In particular, prices are proportional to the sum of centralities, and an individual's consumption depends on how central she is relative to others in the network. Inequalities in wealth and connections reinforce each other in markets: A transfer of resources from less to more central agents raises prices. As segregated communities become integrated, the poor lose while the rich gain in utility! (JEL: D5, D6, D85)     

适应性市场假说及其在中国资本市场的实证

金融危机近些年爆发频繁,传统市场理论如有效市场假说和行为金融面对复杂的现实金融世界未能给出合理解释.Lo提出的适应性市场假说则弥合了这两个学派的分歧,逐渐引起了学术界的重视.本文尝试从动态市场效率、时变贝塔和技术交易策略演变这三个角度对适应性市场假说能否解释我国资本市场进行实证研究.研究发现:我国股票市场效率在动态变化,无效的时段与金融危机或政策巨变等重大事件联系密切;股市风格指数贝塔随市场环境变化而改变;技术交易策略绩效随投资者适应环境变化而演变.研究结果表明,适应性市场假说相比有效市场假说和经典资本资产定价模型,能够更好地解释我国资本市场上述现象.最后对投资者如何根据市场环境变化制定适应性投资策略给出几点建议.     

Level‐k Auctions: Can a Nonequilibrium Model of Strategic Thinking Explain the Winner's Curse and Overbidding in Private‐Value Auctions?

This paper proposes a structural nonequilibrium model of initial responses to incomplete‐information games based on “level‐k” thinking, which describes behavior in many experiments with complete‐information games. We derive the model's implications in first‐ and second‐price auctions with general information structures, compare them to equilibrium and Eyster and Rabin's (2005) “cursed equilibrium,” and evaluate the model's potential to explain nonequilibrium bidding in auction experiments. The level‐k model generalizes many insights from equilibrium auction theory. It allows a unified explanation of the winner's curse in common‐value auctions and overbidding in those independent‐private‐value auctions without the uniform value distributions used in most experiments.     

Competition in Financial Innovation

This paper examines the incentives offered by frictionless markets to innovate asset‐backed securities by owners who maximize the assets' values. Assuming identical preferences across investors with heterogeneous risk‐sharing needs, we characterize economies in which competition provides insufficient incentives to innovate so that, in equilibrium, financial markets are incomplete in all (pure strategy) equilibria, even when innovation is essentially costless. Thus, value maximization does not generally result in complete markets.     

Price Inference in Small Markets

This paper investigates the effects of market size on the ability of price to aggregate traders' private information. To account for heterogeneity in correlation of trader values, a Gaussian model of double auction is introduced that departs from the standard information structure based on a common (fundamental) shock. The paper shows that markets are informationally efficient only if correlations of values coincide across all bidder pairs. As a result, with heterogeneously interdependent values, price informativeness may not increase monotonically with market size. As a necessary and sufficient condition for the monotonicity, price informativeness increases with the number of traders if the implied reduction in (the absolute value of) an average correlation statistic of an information structure is sufficiently small.     

All‐Pay Contests

This paper studies a class of games, “all‐pay contests,” which capture general asymmetries and sunk investments inherent in scenarios such as lobbying, competition for market power, labor‐market tournaments, and R&D races. Players compete for one of several identical prizes by choosing a score. Conditional on winning or losing, it is weakly better to do so with a lower score. This formulation allows for differing production technologies, costs of capital, prior investments, attitudes toward risk, and conditional and unconditional investments, among others. I provide a closed‐form formula for players' equilibrium payoffs and analyze player participation. A special case of contests is multiprize, complete‐information all‐pay auctions.     

Why Frequency is Not Well Defined for Engineering Systems with Nonexponential Failure Times

Dr. Yellman proposes to define frequency as “a time‐rate of events of a specified type over a particular time interval.” We review why no definition of frequency, including this one, can satisfy both of two conditions: (1) the definition should agree with the ordinary meaning of frequency, such as that less frequent events are less likely to occur than more frequent events, over any particular time interval for which the frequencies of both are defined; and (2) the definition should be applicable not only to exponentially distributed times between (or until) events, but also to some nonexponential (e.g., uniformly distributed) times. We make the simple point that no definition can satisfy (1) and (2) by showing that any definition that determines which of any two uniformly distributed times has the higher “frequency” (or that determines that they have the same “frequency,” if neither is higher) must assign a higher frequency number to the distribution with the lower probability of occurrence over some time intervals. Dr. Yellman's proposed phrase, “time‐rate of events … over a particular time interval” is profoundly ambiguous in such cases, as the instantaneous failure rates vary over an infinitely wide range (e.g., from one to infinity), making it unclear which value is denoted by the phrase “time‐rate of events.”     

Valuing Dealers' Informational Advantage: A Study of Canadian Treasury Auctions

In many financial markets, dealers have the advantage of observing the orders of their customers. To quantify the economic benefit that dealers derive from this advantage, we study detailed data from Canadian Treasury auctions, where dealers observe customer bids while preparing their own bids. In this setting, dealers can use information on customer bids to learn about (i) competition, that is, the distribution of competing bids in the auction, and (ii) fundamentals, that is, the ex post value of the security being auctioned. We devise formal hypothesis tests for both sources of informational advantage. In our data, we do not find evidence that dealers are learning about fundamentals. We find that the “information about competition” contained in customer bids accounts for 13–27% of dealers' expected profits.     

Gray Markets and Supply Chain Incentives

“Gray markets” are unauthorized channels that distribute a branded product without the manufacturer's permission. Since gray markets are not officially sanctioned by the manufacturer, their existence is assumed to hurt the manufacturer. Yet manufacturers sometimes tolerate or even encourage gray market activities. We investigate the incentives of a manufacturer and its authorized retailer to engage in (or tolerate) gray markets. The firms need to consider the trade‐off between the positive effects of a gray market (price discrimination and cost savings) and the negative effects (cannibalization of sales and a loss in consumer valuation). Generally, gray markets can be categorized into two types: (i) a “local gray market,” where a retailer diverts products to unauthorized sellers operating in the same region as the retailer; and, (ii) “bootlegging,” where the retailer diverts products to unauthorized sellers in another market where the manufacturer sells through a direct channel. We characterize the equilibrium in each type of gray market and identify conditions under which the retailer will divert products to the gray market. Incentive problems are more complicated when the retailer bootlegs and, in this case, we show that conflicting incentives may lead to the emergence of a gray market where both the manufacturer's and retailer's profits decrease.     

Coping with Gray Markets: The Impact of Market Conditions and Product Characteristics

Gray markets, also known as parallel imports, have created fierce competition for manufacturers in many industries. We analyze the impact of parallel importation on a price‐setting manufacturer that serves two markets with uncertain demand, and characterize her policy against parallel importation. We show that ignoring demand uncertainty can take a significant toll on the manufacturer's profit, highlighting the value of making price and quantity decisions jointly. We find that adjusting prices is more effective in controlling gray market activity than reducing product availability, and that parallel importation forces the manufacturer to reduce her price gap while demand uncertainty forces her to lower prices. Furthermore, we explore the impact of market conditions (such as market base, price sensitivity, and demand uncertainty) and product characteristics (“fashion” vs. “commodity”) on the manufacturer's policy towards parallel importation. We also provide managerial insights about the value of strategic decision‐making by comparing the optimal policy to the uniform pricing policy that has been adopted by some companies to eliminate gray markets entirely. The comparison indicates that the value of making price and quantity decisions strategically is highest for moderately different market conditions and non‐commodity products.     

Toyota's approach to alternative technology vehicles: The power of diversification strategies

While the “quality revolution” of the 80's and the “oil crisis” of the 70's dramatically altered the automotive industry, a new and potentially more influential issue is emerging—the pursuit of an environmentally friendly vehicle. This “green car,” or “eco car,” has become the new “holy grail” of automotive achievement and has the world's largest automakers racing to find a solution that satisfies environmental regulations, rapidly expanding new markets, and consumer preferences alike.Toyota Motor Corporation has chosen to follow several paths simultaneously to attain this seemingly elusive goal. Their twin-tiered technological approach focuses on improving the traditional interval combustion engine (ICES) and developing alternative powertrain technologies, including electric vehicles (EVs), fuel cells and hybrids (a combination of the ICE and EV). Toyota's strategy is to establish proficiency, but not dominance, in a number of the possible alternatives to the current automobile. Toyota strategists believe this is the best tactic for dealing with the uncertainty and risk prevalent in the search for the “green car”.     

Insider Trading With a Random Deadline

We consider a model of strategic trading with asymmetric information of an asset whose value follows a Brownian motion. An insider continuously observes a signal that tracks the evolution of the asset's fundamental value. The value of the asset is publicly revealed at a random time. The equilibrium has two regimes separated by an endogenously determined time T. In [0, T), the insider gradually transfers her information to the market. By time T, all her information has been transferred and the price agrees with the market value of the asset. In the interval [T, ∞), the insider trades large volumes and reveals her information immediately, so market prices track the market value perfectly. Despite this market efficiency, the insider is able to collect strictly positive rents after T.     

Moral Hazard Contracting and Private Credit Markets

This paper studies the impact of credit markets on optimal contracting, when the agent's “interim preference” over upcoming contracts is private information because personal financial decisions affect it via the wealth effect. The main result is a severe loss of incentive provision: equilibrium contracts invariably cause the agent to shirk (i.e., exert minimal effort) if the agent's private financial decision precedes moral hazard contracting. The basic intuition is that committing on another private variable, other than the effort level, exposes the parties to further exploitation of efficient risk‐sharing by relaxing the incentive constraint that was binding ex ante, unless the risk‐sharing was fully efficient to begin with.     

Equilibrium in Continuous‐Time Financial Markets: Endogenously Dynamically Complete Markets

We prove existence of equilibrium in a continuous‐time securities market in which the securities are potentially dynamically complete: the number of securities is at least one more than the number of independent sources of uncertainty. We prove that dynamic completeness of the candidate equilibrium price process follows from mild exogenous assumptions on the economic primitives of the model. Our result is universal, rather than generic: dynamic completeness of the candidate equilibrium price process and existence of equilibrium follow from the way information is revealed in a Brownian filtration, and from a mild exogenous nondegeneracy condition on the terminal security dividends. The nondegeneracy condition, which requires that finding one point at which a determinant of a Jacobian matrix of dividends is nonzero, is very easy to check. We find that the equilibrium prices, consumptions, and trading strategies are well‐behaved functions of the stochastic process describing the evolution of information. We prove that equilibria of discrete approximations converge to equilibria of the continuous‐time economy.     

Dynamic Mechanism Design: A Myersonian Approach

We study mechanism design in dynamic quasilinear environments where private information arrives over time and decisions are made over multiple periods. We make three contributions. First, we provide a necessary condition for incentive compatibility that takes the form of an envelope formula for the derivative of an agent's equilibrium expected payoff with respect to his current type. It combines the familiar marginal effect of types on payoffs with novel marginal effects of the current type on future ones that are captured by “impulse response functions.” The formula yields an expression for dynamic virtual surplus that is instrumental to the design of optimal mechanisms and to the study of distortions under such mechanisms. Second, we characterize the transfers that satisfy the envelope formula and establish a sense in which they are pinned down by the allocation rule (“revenue equivalence”). Third, we characterize perfect Bayesian equilibrium‐implementable allocation rules in Markov environments, which yields tractable sufficient conditions that facilitate novel applications. We illustrate the results by applying them to the design of optimal mechanisms for the sale of experience goods (“bandit auctions”).     

Isotone Equilibrium in Games of Incomplete Information

An isotone pure strategy equilibrium exists in any game of incomplete information in which each player's action set is a finite sublattice of multidimensional Euclidean space, types are multidimensional and atomless, and each player's interim expected payoff function satisfies two “nonprimitive conditions” whenever others adopt isotone pure strategies: (i) single‐crossing in own action and type and (ii) quasi‐supermodularity in own action. Conditions (i), (ii) are satisfied in supermodular and log‐supermodular games given affiliated types,and in games with independent types in which each player's ex post payoff satisfies supermodularity in own action and nondecreasing differences in own action and type. This result is applied to provide the first proof of pure strategy equilibrium existence in the uniform price auction when bidders have multi‐unit demand, nonprivate values, and independent types.