Bubbles for Fama

We evaluate Eugene F. Fama's claim that stock prices do not exhibit price bubbles. Based on US industry returns (1926?2014) and international sector returns (1985?2014), we present four findings (1) Fama is correct in that a sharp price increase of an industry portfolio does not, on average, predict unusually low returns going forward; (2) such sharp price increases predict a substantially heightened probability of a crash but not of a further price boom; (3) attributes of the price run-up, including volatility, turnover, issuance, and the price path of the run-up, help forecast an eventual crash; and (4) these attributes also help forecast future returns. Results hold similarly in US and international samples.     

Security design,market risk and round quotes in the treasury bond market

Prior literature finds that the tendency of price-endings to cluster on rounder fractions increases with price volatility. We estimate the separate influences and relative importance of the determinants of price volatility, security design and market risks. Our data is from a market setting that is ideal for isolating and studying the relations of interest. Results for both quote and trade prices indicate that the tendency to use round price-endings increases with both a security’s inherent risk, attributable to security design, and variation over time in market risks. Security design influences clustering more than market risks, but market risks are influential in determining clustering once security design is fixed. The estimated effects are strongest in the on-the-run market segment where liquidity facilitates the aggregation of information into price.     

Macroeconomic Announcements and the Distribution of Price-Endings in the U.S. Treasury Market

We investigate how new information impacts quote clustering in the bond market. We find that clustering, along with quote activity, price volatility and bid-ask spreads, increases sharply in the minutes following releases of macroeconomic news. Each returns to near-normal levels within the hour. Effects are strongest for more liquid on-the-run notes and for the announcements typically associated with substantial information flow. The strong positive comovement of clustering, quote activity, price volatility, and bid-ask spreads supports the conclusion that innovations of these variables are endogenous to the arrival and incorporation of information into prices.     

Do small shareholders count?

We hypothesize that age similarity among small shareholders acts as an implicit coordinating device for their actions and, thus, could represent an indirect source of corporate governance in firms with dispersed ownership. We test this hypothesis on a sample of Swedish firms during the 1995-2000 period. Consistent with our hypothesis, we find that compared with shareholders of differing ages, same-age noncontrolling shareholders sell more aggressively following negative firm news; firms with more age-similar small shareholders are more profitable and command higher valuation; and an increase (decline) in a firm's small shareholder age similarity brings a significantly large increase (decline) in its stock price. The last effects are more pronounced in the absence of a controlling shareholder.     

Why do intermediaries divert search?

We analyze the incentives to divert search for an information intermediary who enables buyers (consumers) to search affiliated sellers (stores). We identify two original motives for diverting search (i.e., inducing consumers to search more than they would like): (i) trading off higher total consumer traffic for higher revenues per consumer visit; and (ii) influencing stores’ choices of strategic variables (e.g., pricing). We characterize the conditions under which there would be no role for search diversion as a strategic instrument for the intermediary, thereby showing that it occurs even when the contracting space is significantly enriched. We then discuss several applications related to online and brick‐and‐mortar intermediaries.     

Dynamically stable preferences

In the framework of dynamic choice under uncertainty, we define dynamic stability as a combination of two assumptions prevalent in the literature: dynamic consistency and the requirement that updated preferences have the same “structure” as ex ante ones. Dynamic stability also turns out to be a defining characteristic of the multiplier preferences of Hansen and Sargent (2001) [24] within the scope of variational preferences. Generally, for any class of invariant preferences, dynamic stability is shown to be connected to another independent property — consequentialism.     

A reference-dependent representation with subjective tastes

Experimental and empirical evidence documents instances where the presence of an inferior option in a menu increases the attractiveness of the better options from that menu and thus distorts the normative ranking across menus. We analyze the case when in addition to this so called context-effects bias there is also a concern for flexibility, in the spirit of the literature initiated by Kreps (1979) and Dekel et al. (2001). Since the context-effects bias and the desire for flexibility both increase the inclination of a decision maker to choose larger menus, our analysis allows the disentangling of the effect of the behavioral bias from the effect of the rational desire from flexibility. We find a weak condition on the set of ex post preferences under which the two effects are identifiable. We show that our representation is essentially unique. From a methodological viewpoint, our paper provides a novel technique of identifying probabilities on the state space of subjective uncertainty introduced by Dekel et al. (2001) when this state space is infinite. This method renders the infinite state space essentially finite with respect to a certain salient property.     

Multivariate Cox Hidden Markov models with an application to operational risk

ABSTRACT

Modeling multivariate time-series aggregate losses is an important actuarial topic that is very challenging due to the fact that losses can be serially dependent with heterogeneous dependence structures across loss types and business lines. In this paper, we investigate a flexible class of multivariate Cox Hidden Markov Models for the joint arrival process of loss events. Some of the nice properties possessed by this class of models, such as closed-form expressions, thinning properties and model versatility are discussed in details. We provide the expectation-maximization (EM) algorithm for efficient model calibration. Applying the proposed model to an operational risk dataset, we demonstrate that the model offers sufficient flexibility to capture most characteristics of the observed loss frequencies. By modeling the log-transformed loss severities through mixture of Erlang distributions, we can model the aggregate losses. Finally, out-of-sample testing shows that the proposed model is adequate to predict short-term future operational risk losses.     

Exclusivity and Control

We model competition between content distributors (platforms) for content providers, and show that whether or not content is exclusive or “multihomes” depends crucially on whether or not content providers maintain control over their own pricing to consumers: if content providers sell their content outright and relinquish control, they will tend to be exclusive; on the other hand, if content providers maintain control and only “affiliate” with platforms, then multihoming is sustainable in equilibrium. We show that the outcome under affiliation depends on the tradeoff between platform rent extraction (which increases in exclusivity) and content rent extraction (which increases in multihoming), and demonstrate that the propensity for exclusivity can be increasing, decreasing, or even nonmonotonic in content quality. Finally, if a content provider internalizes the effect of its own price on platform demand, we prove that a platform that already has exclusive access to content may prefer to relinquish control over content pricing to the content provider in order to reduce price competition at the platform level.     

A simple search model of money with heterogeneous agents and partial acceptability

Summary. Simple search models have equilibria where some agents accept money and others do not. We argue such equilibria should not be taken seriously. This is unfortunate if one wants a model with partial acceptability. We introduce heterogeneous agents and show partial acceptability arises naturally and robustly. There can be multiple equilibria with different degrees of acceptability. Given the type of heterogeneity we allow, the model is simple: equilibria reduce to fixed points in [0,1]. We show that with other forms of heterogeneity equilibria are fixed points in set space, and there is no method to reduce this to a problem in R¹.Received: 4 September 2002, Revised: 23 September 2002JEL Classification Numbers: C78, E40.A. Shevchenko, R. Wright: We thank seminar participants at the Federal Reserve Bank of Cleveland, Indiana University, Purdue University, University of Toronto, the 2002 Midwest Macroeconomics Conference at Vanderbilt University, and the 2001 Conference on Economic Dynamics at the University of Essex. The National Science Foundation and the Federal Reserve Bank of Cleveland provided financial support. Braz Ministerio de Camargo and Gabriel Camera provided some helpful suggestions. Correspondence to: R. Wright