理论论文

ABSTRACT Why do fire sales occur if many risks are hedgeable? We study a version of Brunnermeier and Sannikov (2014, American Economic Review 104, 379–421) in which all fundamental risks can be hedged frictionlessly. Our analysis shows that fire sales are inherently self‐fulfilling. Fundamental shocks can never cause fire sales, and an efficient, safe equilibrium exists. On the other hand, there exists an equilibrium in which agents coordinate fire sales on nonfundamental shocks. A simple refinement based on vanishingly small perceived fundamental risk eliminates the safe equilibrium and selects the fire‐sale equilibrium as the unique outcome.

We show that the formalization of representativeness (Kahneman and Tversky, 1972, Cognitive Psychology, 3, 430–454) developed by Gennaioli and Shleifer (2010, The Quarterly Journal of Economics, 125, 1399–1433) features an intrinsic connection between uncertainty and overreaction. In the time series domain, we develop this connection in a smooth version of diagnostic expectations (DE), where overreaction varies smoothly with uncertainty. Intuitively, under smoothness, lower uncertainty leaves less room for representativeness to distort beliefs. Smooth DE provides a joint, parsimonious micro-foundation for key features of survey data: overreaction to news, stronger overreaction at longer horizons, overconfidence in subjective uncertainty, and a new stylized fact documented here—overreaction intensifies with higher uncertainty. An analytical Real Business Cycle model with Smooth DE accounts for survey overreaction and overconfidence, as well as three salient business cycle properties: asymmetry, countercyclical macro volatility, and countercyclical micro volatility.

Using transaction-level data from the Korean tri-party repo market, we study how repo contract terms interact with collateral quality. Both haircuts and interest rates rise with collateral risk, consistent with existing evidence. Conditional on collateral quality, however, we find a trade-off: a one-percentage-point increase in the spread is associated with a 1.3-percentage-point reduction in the haircut. The same increase in the interest rate is associated with a smaller reduction in the haircut under heightened market uncertainty, indicating that insurance against default becomes more valuable as default risk rises. We show that the interaction between lenders’ incentives to acquire information and borrowers’ opportunistic default risk explains both the positive unconditional relationship and the negative conditional relationship between haircuts and interest rates.

ABSTRACT We examine optimal capital requirements in a quantitative general equilibrium model with banks exposed to nondiversifiable borrower default risk. Contrary to standard models of bank default risk, our framework captures the limited upside, but significant downside risk of loan portfolio returns. This helps to reproduce the frequency and severity of twin defaults : simultaneously high firm and bank defaults. Hence, the optimal bank capital requirement, which trades off a lower frequency of twin defaults against restricting credit provision, is higher than under default risk models which underestimate the impact of borrower default on bank solvency.

We provide a theorem on the role of risk and risk attitudes in macroeconomic models that clarifies and extends the Tallarini (2000) separation result. Under (1) separation of intertemporal and risk preferences, (2) separation of drivers of first and higher moments in the model primitives, and (3) approximate linearity of constraints, risk aversion and time-varying risk are irrelevant for the elasticity of any endogenous variable with respect to state variables that don’t drive variation in higher moments. We discuss how models generate a more prominent role for risk by “breaking” or “adapting” to the assumptions in the theorem.

ABSTRACT This paper provides novel empirical evidence that cash‐rich firms have higher equity payouts and higher stock prices in response to expansionary monetary policy surprises. Stock prices rise despite weak cash‐flow, investment, and credit responses to monetary policy. I rationalize the empirical evidence in a heterogeneous‐firm New Keynesian model where firms finance investment with cash and equity issuance. Monetary easing weakens precautionary cash demand, leading cash‐rich firms to optimally allocate excess funds to shareholders. Since payouts are procyclical, cash‐rich firms earn higher returns in expansionary periods. My findings highlight a payout channel through which monetary policy impacts asset prices.

We theoretically and experimentally study centralized college admissions in which colleges evaluate students under a ‘translucent’ admission system and students can learn each college’s suitability through costly information acquisition. In centralized matching via Gale and Shapley’s deferred acceptance algorithm, students decide whether to acquire information before submitting their rank-order lists. However, uncertainty about the final assignment lowers the expected gain from learning, thereby reducing social welfare, compared to a scenario without such uncertainty. Our experiments demonstrate that the welfare loss is greater with more opaque admission systems. The empirical social welfare obtained in our experimental treatments is consistently lower than the theoretical welfare, and we identify non-equilibrium learning as a main contributor.

This article examines, both theoretically and experimentally, the welfare implications of implementing symmetric bid caps in lobbying competitions. We model lobbying games as lottery contests with two radicals and one centrist, where all players strictly prefer to win. However, if they lose, radicals prefer to lose to a centrist rather than to the opposing radical. We establish the existence and uniqueness of equilibrium and find that, in the absence of a bid cap, radicals may bid aggressively enough to drive the centrist out of the competition, thereby preventing the social welfare-maximizing outcome. Consequently, implementing a bid cap enhances social welfare in two ways: it reduces aggregate expenditure and increases the likelihood of the centrist winning. Our experimental results qualitatively align with the theoretical predictions. However, we also identify and address notable behavioral patterns: in contrast to the vast experimental literature (Sheremeta, 2013) on contests, aggregate bids do not exceed theoretical predictions in all treatments.

We provide a strategic model of the formation of production networks that subsumes the standard general equilibrium approach. The objective of firms in our setting is to choose their supply relationships so as to maximize their profit at the general equilibrium that unfolds. We show that this objective is equivalent to the maximization by the firms of their eigenvector centrality in the production network. As is common in network formation games based on centrality, there are multiple Nash equilibria in our setting. We have investigated the characteristics and the social efficiency of these equilibria in a stylized version of our model representing international trade networks. We show that the impact of network structure on social welfare is firstly determined by a trade-off between costs of increasing process complexity and positive spillovers on productivity induced by the diversification of the input mix. We further analyze a variant of our model that accounts for the risks of disruption of supply relationships. In this setting, we characterize how social welfare depends on the structure of the production network, the spatial distribution of risks, and the process of shock aggregation in supply chains. We finally show that simple trade policies characterized by sets of links that are either prevented or catalyzed can be a powerful equilibrium selection device.

This paper investigates how to persuade multiple interacting receivers under arbitrary equilibrium selection and when receivers’ preferences may exhibit psychological traits. Our main result characterizes the conditions under which the sender can categorize information using partitions and then disclose partition-related information without altering the equilibrium outcome. This finding broadens the traditional direct approach based on the revelation principle, which categorizes messages solely by equilibrium actions. Consequently, our results support a generalized direct approach, which we apply to study information disclosure in fostering fairness within groups where members may demonstrate altruistic behaviors.

We extend global games á la Carlsson and van Damme (1993) to environments where the risk-dominant equilibrium is selected even if there is no dominance solvable game in the underlying class of games. Strict dominance can emerge in the global game from strategic uncertainty due to discrete payoff changes in underlying games, and we provide sufficient conditions on payoff changes that warrant iterated dominance of the risk-dominant equilibrium. Thus, strategic uncertainty creates strictly dominant actions as well as fostering iterated dominance, in contrast to global games hitherto where strategic uncertainty does only the latter. Discrete payoff changes tend to arise, in particular, in situations where a public good can be provided with varying degrees of coordination depending on the state, so that coordinating actions can be strategic substitutes and free-riding incentives are present. We illustrate our findings in a stylized public good provision model.

ABSTRACT I propose a dynamic equilibrium model of rental markets that endogenously gives rise to defaults on rents and evictions. In the model, eviction protections make it harder to evict delinquent renters, but higher default costs to landlords increase equilibrium rents. I quantify the model using micro data on evictions, rents, and homelessness. I find that stronger eviction protections exacerbate housing insecurity and lower welfare. The key empirical driver of this result is the persistent nature of risk underlying rent delinquencies. Rental assistance reduces housing insecurity and improves welfare because it lowers the likelihood that renters default ex ante.

This paper studies a model with wage bargaining, random on-the-job search and renegotiation. Wages are determined by a bargaining process in which the firm and the worker alternate in making offers and there is a probability that this process breaks down. In the model, a given wage contract ends at a Poisson rate, and then the firm and the worker bargain over a new wage. In this setting, a higher wage decreases the firm's markup, but this effect is partly offset by lowering turnover, which increases match surplus. This increase in match surplus enables the worker to capture a higher share of the surplus. This positive effect of a higher wage on match surplus diminishes when they renegotiate more frequently. Eventually, as the contract length tends to zero, the equilibrium of the model converges to the equilibrium payoffs discussed by Pissarides (1994). My model thereby justifies using the Nash bargaining solution with perfectly transferable values in models with on-the-job search. In contrast, when the Poisson rate goes to zero, the equilibrium in the model, which I show to be unique, converges to one of the equilibria found by Shimer (2006).

We consider many-to-many matching with contracts where each agent can sign multiple contracts with the same agent. In other words, the unitarity condition is not assumed in this model. We offer a weaker substitutability condition called substitutability across doctors, which is a generalization of unilateral substitutability. We show that if every hospital’s choice function satisfies substitutability across doctors and every doctor’s choice function is responsive, then a stable outcome exists. We establish this result by generalizing the cumulative offer process. Moreover, we propose an even weaker substitutability condition that incorporates observability of doctors’ contract offers during the algorithm. The same algorithm guarantees the existence of a stable outcome even when substitutability across doctors is replaced with the weaker condition. We additionally present a specific class of choice functions satisfying the weaker condition that can be applied to a temporary staffing market, particularly in which temp agencies may assign multiple temporary workers to each client.

ABSTRACT The deposit franchise is valuable because banks pay below‐market deposit rates. However, if depositors leave, its value vanishes. This can trigger runs by uninsured depositors, even if banks hold fully liquid assets. Because the franchise value increases with interest rates, runs are more harmful, and hence likelier, when rates are high. Banks can deter runs by shortening asset duration, but this risks insolvency if rates fall. Avoiding both runs and insolvency requires capital covering the potential loss of the uninsured deposit franchise. We estimate deposit franchise values and use them to identify vulnerable banks during the 2023 regional bank crisis.

ABSTRACT We propose a theory of coordination and influence among blockholders. Privately informed activists time their trades in sequence to lower acquisition costs, prompting a strategic use of order flows: leader activists create trading gains for their followers, ultimately influencing their willingness to bear greater value‐enhancing intervention costs. Through this channel, informed trades can exhibit predictability, in sharp contrast with Kyle (1985, Econometrica 53, 1315–1335). We explain how this novel predictability shapes free‐rider problems affecting governance, and how it produces price abnormalities analogous to those documented empirically. We also uncover how private information interdependence can be a key catalyst for the mechanism studied.

In a recent paper, Lin & Palfrey (2024) developed a theory of cognitive hierarchies (CH) in sequential games and observed that this solution concept is not reduced-normal-form invariant. In this paper I qualify and explain this observation. I show that the CH model is normal-form invariant, and that the differences arising from the application of the CH model to the reduced normal form depend only on how randomization by level-0 types is modeled. Indeed, while the uniform behavior strategy in the extensive form yields the uniform mixed strategy in the normal form, the latter does not correspond to the uniform randomization in the reduced normal form, because different reduced strategies may correspond to sets of equivalent strategies with different cardinalities. I also comment on (i) the invariance of the CH model to some transformations of the sequential game, and (ii) the independence of conditional beliefs about co-players' level-types.

We study optimal service allocation through queues when agents have homogeneous preferences and must be incentivized to enter and remain in the queue. The designer controls entry, exit, service priority, and information about queue priorities. Under a mild regularity condition, the optimal mechanism admits agents only up to a cutoff queue length, never removes admitted agents, serves them according to a first-come, first-served (FCFS) rule, and provides no information beyond recommendations. FCFS is also necessary for optimality in a rich domain. The result identifies a new role for queue disciplines in regulating agents’ beliefs and dynamic incentives, and uncovers a hitherto unrecognized virtue of FCFS in this regard.

ABSTRACT We develop a unified theory of blockholder governance and the voting premium in a setting without takeovers or controlling shareholders. A voting premium emerges when a minority blockholder can influence shareholder composition by accumulating votes and buying shares from dissenting shareholders. Our theory reconciles conflicting empirical findings by showing that standard measures of the voting premium often misrepresent the true value of voting rights, increased conflicts between the blockholder and small shareholders do not necessarily raise the voting premium, and the voting premium can even turn negative when small shareholders free‐ride on the blockholder's trades.

We analyze optimal procurement contracts when suppliers learn about project costs over time and retain an ex-post right to exit. In the first period, the firm observes a private signal on the likelihood of high costs; in the second, it learns the realized cost type and decides whether to continue or exercise its outside option. We show that when exit opportunities are sufficiently attractive, the optimal mechanism pools all first-period signals and reduces to a cost-plus contract, with payments tied only to realized, verifiable costs. Attempts to elicit cost forecasts ex-ante backfire: firms strategically under-report expectations, triggering exit in high-cost states and generating overruns. This provides a mechanism-based interpretation of cost overruns as failures of incentive design. Finally, we demonstrate that more generous outside options can raise procurement costs and lower firm profits, identifying conditions where limiting exit rights is ex-ante Pareto improving. (JEL D82, D86, H57)