Portfolio choice, attention allocation, and price comovement

This paper models the attention allocation of portfolio investors. Investors choose the composition of their information subject to an information flow constraint. Given their expected investment strategy in the next period, which is to hold a diversified portfolio, in equilibrium investors choose to observe one linear combination of asset payoffs as a private signal. When investors use this private signal to update information about two assets, changes in one asset affect both asset prices and may lead to asset price comovement. The model also has implications for the transmission of volatility shocks between two assets.     

Over-the-counter loans,adverse selection,and stigma in the interbank market

We study a model of interbank credit where physical and informational frictions limit the opportunities for intertemporal trade among banks and outside investors. Banks obtain loans in an over-the-counter market (involving search, bilateral matching, and negotiations over the terms of the loan) and hold assets of heterogeneous quality that in turn determine their ability to repay those loans. When asset quality is not observable by outside investors, information about the actions taken by a bank in the loan market may influence prices in the asset market. In particular, under some conditions, borrowing from the central bank can be regarded as a negative signal about the quality of the borrower?s assets and banks may be willing to borrow in the market at rates higher than the one offered by the central bank.     

ADVERSE SELECTION WITH HETEROGENEOUSLY INFORMED AGENTS

A model of over-the-counter markets is proposed. Some asset buyers are informed in that they can identify high-quality assets. Sellers with private information choose what type of buyers they want to trade with. When the measure of informed buyers is low, a unique equilibrium exists, and interestingly, price, trading volume and welfare typically decrease with more informed buyers. When the measure of informed buyers is intermediate, multiple equilibria arise. A switch from one equilibrium to another can lead to large drops in liquidity, price, trading volume, and welfare, like a financial crisis. Implications of an endogenous measure of informed buyers are also studied.     

Herding in delegated portfolio management: When is comparative performance information desirable?

We address the issue of investors’ asset allocation decisions when portfolio management is delegated to an agent. Contrary to predictions from traditional financial theory, it is shown that investors may not induce their manager to allocate funds to the asset with the highest return. Instead they may herd in their asset allocation decision and induce trade in a particular asset, because another manager is trading in it and despite the presence of a more profitable alternative. Doing so allows investors to write an efficiency-improving relative-performance contract. On the other hand, herding leads investors to design wage contracts strategically, resulting in more aggressive and thus less profitable trade in equilibrium. We show that herding occurs, when the cost of information is high, information precision is low and when managers are sufficiently risk averse. Moreover, when investors can decide whether or not to disclose information about their manager's performance, they will not do so.     

Information Markets and the Comovement of Asset Prices

Traditional asset pricing models predict that covariance between prices of different assets should be lower than what we observe in the data. This paper introduces markets for information that generate high price covariance within a rational expectations framework. When information is costly, rational investors only buy information about a subset of the assets. Because information production has high fixed costs, competitive producers charge more for low-demand information than for high-demand information. The low price of high-demand information makes investors want to purchase the same information that others are purchasing. When investors price assets using a common subset of information, news about one asset affects the other assets' prices; asset prices comove. The cross-sectional and time-series properties of comovement are consistent with this explanation.     

Do Irrational Investors Destabilize?

In a financial market where all investors have valuable private information, full rationality requires that investors have an unlimited ability of figuring out the equilibrium model. Instead, I assume that due to a lack of knowledge or experience, some investors do not know the equilibrium model and use only their private information in forming their demand. By investigating the investment behavior of these “boundedly rational” investors and contrasting it with that of the rational ones, I find that in a market where the two kinds of investors coexist, it is the boundedly rational investors who contribute to price stability. The welfare implication is that, although each investor benefits from conditioning his asset demand on the information transmitted by the equilibrium price, it can happen that all investors lose by doing so because the equilibrium price becomes too volatile.     

WHO SEARCHES?*

We consider a directed search model with buyers and sellers and determine whether buyers look for sellers or vice versa. The buyers and sellers can choose to search or wait; what they do in equilibrium depends on the relative size of the two populations and the price formation mechanism. We study bargaining and auctions and find that when one population is much larger than the other the former searches and the latter waits. Under auction with roughly equal populations some buyers and sellers search and some wait. Our results challenge the practice of postulating who searches and who waits.     

Buyer search and price dispersion: a laboratory study

We study markets with costly buyer search in which sellers simultaneously post prices. Buyers costlessly observe one or (with probability 1−q) two of the posted prices, and can accept one or pay to search again. The experiment varies q, the search cost, and the number of buyers. Equilibrium theory predicts a unified very low (high) price for q=0 (q=1) and predicts specific distributions of dispersed prices for q=1/3 and 2/3. Actual prices conform closely to the predictions in some treatments. Buyers’ reservation prices are biased away from the extremes, however, and sellers’ prices have positive autocorrelation and cross-sectional correlation.     

消费习惯、异质偏好与动态资产定价:纯交换经济情形

本文用Chan和Kogan、Bask和Cuoco等的方法考虑纯交换经济下的定价问题,我们引进了两个投资者:一个具有外在性消费习惯;一个不具有消费习惯。我们重点考察消费习惯对投资者的最优消费规则的影响以及对资产价格的确定。此外,我们还考虑了对数效用函数下,消费习惯以差的形式出现的情形下的消费规则和定价问题。我们发现当两个投资者中一个具有消费习惯而另一个不具有该习惯时,消费习惯同时改变两个投资者的最优消费规则、消费动态和财富动态。此时的动态资产定价受外在性消费习惯的影响,即时Sharpe比为常数,并等于同质量经济下的即时Sharpe比。同时,如果考虑对数效用函数下消费习惯以差的形式出现,则即时Sharpe比是时变的,反周期的。     

Collateral fluctuations in a monetary economy

This paper studies economy-wide fluctuations that occur endogenously in the presence of monetary and real assets. Using a standard monetary search model, we consider an economy in which agents can increase consumption, over and above what their liquid monetary asset holdings would allow, pledging real assets as collateral for monetary loans. It is shown that, if the liquidation value of real assets is below full market value, a stable cyclical equilibrium can emerge in consumption and capital around the unstable steady state. We also provide conditions for the existence of cycles of higher order, chaos and sunspot equilibria.     

Internal rationality, imperfect market knowledge and asset prices

We present a decision theoretic framework in which agents are learning about market behavior and that provides microfoundations for models of adaptive learning. Agents are ‘internally rational’, i.e., maximize discounted expected utility under uncertainty given dynamically consistent subjective beliefs about the future, but agents may not be ‘externally rational’, i.e., may not know the true stochastic process for payoff relevant variables beyond their control. This includes future market outcomes and fundamentals. We apply this approach to a simple asset pricing model and show that the equilibrium stock price is then determined by investors? expectations of the price and dividend in the next period, rather than by expectations of the discounted sum of dividends. As a result, learning about price behavior affects market outcomes, while learning about the discounted sum of dividends is irrelevant for equilibrium prices. Stock prices equal the discounted sum of dividends only after making very strong assumptions about agents? market knowledge.     

Mode of International Investment and Endogenous Risk of Expropriation

This paper analyzes the relationship between the mode of international investment and institutional quality. Foreign investors from a capital‐rich North can either purchase productive assets in a capital‐poor South and transfer their capital within integrated multinational firms or they can form joint ventures with local asset owners. The South is ruled by an autocratic elite that may use its political power to expropriate productive assets. The expropriation risk lowers the incentive to provide specific capital in an integrated firm and distorts the decision between joint ventures and integrated production. We determine the equilibrium risk of expropriation in this framework and the resulting pattern of international production. We also analyze as to how globalization, which is reflected in a decline in investment costs, influences institutional quality.     

High profit equilibria in directed search models

We consider a model of directed search where the sellers are allowed to post mechanisms with entry fees. Regardless of the number of buyers and sellers, the sellers are able to extract all the surplus of the buyers by introducing entry fees and making price schedules positively sloped in the number of buyers arriving to their shops. This is in contrast to results that are achieved for large markets under the assumption that sellers cannot influence the utility of any particular buyer (market utility assumption), in which case buyers obtain strictly positive rents. If there is a bound on the prices or on the entry fees that can be charged, then the equilibrium with full rent extraction does not exist any more, and the market utility assumption is restored for large markets.     

Rational expectations,difference of opinions and asset pricing

This article applies the concept of relative overconfidence (the measure of how heavily investors depend on others’ information) to combine the rational expectations equilibrium (REE) and difference of opinions (DO) models. And we discuss the effects of relative overconfidence on asset price efficiency and trading volume. We find that when investors hold assets to maturity, relative overconfidence has no effect on price efficiency and trading volume; however, when investors speculate, relative overconfidence reduces price informativeness and trading volume, because investors will reckon asset prices as more noisy and find it meaningless to speculate on capital gains based on their private information. Our results highlight the role of speculation in differentiating REE and DO models and influencing the effects of overconfidence.     

连续进化金融模型与全局渐进化稳定策略

本文运用达尔文生物进化论思想研究连续交易金融市场选择的动态变化及一般均衡规律。本文发现并证明了:金融资产“赢利”的充要条件是该资产相对股息大于相对股价;投资比例等于股息分发比例的简单混合策略是全局渐近进化稳定策略;在均衡条件下,对应的金融资产价格等于该资产股息占总股息的比例的数学期望;市场变异或金融创新是有效市场形成的动力;全局渐近进化稳定策略业绩可能在某些时候不是最好的,但只要其初始财富大于零,最终将控制市场上的所有财富,而简单混合策略,可能在某个时候业绩优良,然而,在市场存在全局渐近进化稳定策略的条件下,只要其初始财富份额小于1,最终控制的财富趋向于零,从而被市场所淘汰。     

Rationally mispriced assets in equilibrium

We present a simple model of trading in a financial market where agents are asymmetrically informed and information is transmitted through the price system. We characterize the equilibrium for this economy and show that ‘rational mispricing’ of assets occurs if the price system fails to reveal the insider information accurately. It is argued that the communication of wrong information through equilibrium prices is compatible with full rationality on the part of the investors and may explain deviations from the efficient markets hypothesis.     

New financial markets: who gains and who loses

Summary. We evaluate the effects of new financial markets in a two-period incomplete markets model with heterogenous agents. For analytical tractability, we focus on the special case where utility is exponential and risks are normally distributed. We provide a complete characterization of life-cycle consumption and portfolio choice. The effect of new financial markets on individual welfare equals the sum of what we call the portfolio effect and the price effect. The portfolio effect is proportional to the square of the difference between the average exposure to the new asset in the economy and an individual investors exposure adjusted for risk aversion. The portfolio effect is always positive and measures the improved ability of investors to transfer consumption across states. The price effect captures the effect on individual welfare of changes in asset prices. We show that new financial markets drive down the prices of all assets which raises the interest rate and thus affects the ability of investors to transfer consumption across time. The price effect is positive for net savers but can be negative for net borrowers. For net borrower households, the price effect can wipe out the portfolio effect and lead to welfare reductions.Received: 24 July 2003, Revised: 22 March 2004, JEL Classification Numbers: D31, D52, G11, G12.Paul Willen: Thanks to Viral Acharaya, Alberto Bisin, Steve Davis, John Geanakoplos and a thoughtful anonymous referee for helpful comments and suggestions. Thanks also to seminar audiences at Stanford, Berkeley and at the 2001 Stony Brook workshop on incomplete markets for comments and suggestions. I gratefully acknowledge research support from the Graduate School of Business at the University of Chicago.     

Investors’ heterogeneity and tranching

The article presents a theoretic model of tranching in asset securitization. When potential buyers are heterogeneous in the constraint on their portfolios, we find that senior tranche, which is less risky and created by tranching, will introduce more investors and thus reduce risk exposure to investors. Thus, tranching helps improve the sale’s revenue. We also find that the portfolio constraints of investors are always binding at optimum, which is called marginal rating.     

EDGAR on the internet: The welfare effects of wider information distribution in an experimental market for risky assets

Policies such as the SEC’s Fair Disclosure Rule, and technologies such as SEC EDGAR, aim to disseminate corporate disclosures to a wider audience of investors in risky assets. In this study, we adopt an experimental approach to measure whether this wider disclosure is beneficial to these investors. Price-clearing equilibrium models based on utility maximization and non-revealing and fully-revealing prices predict that in a pure exchange economy, an arbitrary trader would prefer that no investors are informed rather than all are informed; non-revealing theory further predicts that an arbitrary trader would prefer a situation in which all traders are informed rather than half the traders are informed. These predictions can be summarized as “None > All > Half”. A laboratory study was conducted to test these predictions. Where previous studies have largely focused on information dissemination and its effects on equilibrium price and insider profits, we focus instead on traders’ expected utility, as measured by their preferences for markets in which none, half, or all traders are informed. Our experimental result contradicts the prediction and indicates “Half > None > All”, i.e. subjects favor a situation where a random half is informed. The implication is that in addition to testing predictions of price equilibrium, experiments should also be used to verify analytical welfare predictions of expected utility under different policy choices. JEL Classification D82, D53, G14, L86 This work was largely completed while this author was at The Hong Kong University of Science and Technology.     

Are stocks desirable in tax-deferred accounts?

Existing literature suggests that, in order to maximize the tax benefit of retirement accounts, investors should follow a “pecking order” location rule of placing highly taxed assets (e.g., bonds) in a tax-deferred account and lightly taxed assets (e.g., stocks) in a taxable account. Empirical evidence, however, documents that a large number of investors violate this rule. In this paper, we show that such violations can be optimal for risk-averse investors who face portfolio constraints. In particular, while the strategy of placing bonds in the tax-deferred account maximizes the expected level of tax benefit, it may lead to volatile benefits under different realizations of stock returns. By holding a similar portfolio in both accounts, investors can achieve a more balanced growth in the two accounts, minimize the likelihood of violating the constraints in the future and hence “smooth” the volatility of the tax benefit. For some risk-averse investors, this smoothing motive can lead to the observed violation of the pecking order location rule. Our model predicts that such violations are more likely when future tax benefits are more volatile, which can occur, for example, when: (i) the tax rate differential across assets increases over time due either to tax law changes or to tax bracket changes for investors; (ii) asset returns are more volatile; and (iii) investors anticipate large future liquidity needs.