Do social networks prevent bank runs?

We develop, both theoretically and experimentally, a stereotypical environment that allows for coordination breakdown, leading to a bank run. Three depositors are located at the nodes of a network and have to decide whether to keep their funds deposited or to withdraw. One of the depositors has immediate liquidity needs, whereas the other two depositors do not. Depositors act sequentially and observe others actions only if connected by the network. Theoretically, a link connecting the first two depositors to decide is sufficient to avoid a bank run. However, our experimental evidence shows that subjects¿ choice is not affected by the existence of the link per se. Instead, being observed and the particular action that is observed determine subjects¿ choice. Our results highlight the importance of initial decisions in the emergence of a bank run. In particular, Bayesian analysis reveals that subjects clearly depart from predicted behavior when observing a withdrawal.bank runs, coordination failures, experimental evidence, networks

New monetarist economics: methods

This essay articulates the principles and practices of New Monetarism, the authors' label for a recent body of work on money, banking, payments, and asset markets. They first discuss methodological issues distinguishing their approach from others: New Monetarism has something in common with Old Monetarism, but there are also important differences; it has little in common with Keynesianism. They describe the principles of these schools and contrast them with their approach. To show how it works in practice, they build a benchmark New Monetarist model and use it to study several issues, including the cost of inflation, liquidity, and asset trading. They also develop a new model of banking.Monetary policy

Do social networks prevent or promote bank runs? | A társadalmi hálózatok megakadályozzák vagy előmozdítják a bankrohamokat?

We report experimental evidence on the effect of observability of actions on bank runs. We model depositors’ decision-making in a sequential framework, with three depositors located at the nodes of a network. Depositors observe the other depositors’ actions only if connected by the network. Theoretically, a sufficient condition to prevent bank runs is that the second depositor to act is able to observe the first one’s action (no matter what is observed). Experimentally, we find that observability of actions affects the likelihood of bank runs, but depositors’ choice is highly influenced by the particular action that is being observed. Depositors who are observed by others at the beginning of the line are more likely to keep their money deposited, leading to less bank runs. When withdrawals are observed, bank runs are more likely even when the mere observation of actions should prevent them. | Kísérleti úton vizsgáljuk a korábbi döntések megfigyelhetőségének hatását a bankrohamok kialakulására. Három betétes egy társadalmi hálózat csomópontjait jeleníti meg és egymás után hozzák a döntéseiket. A betétesek megfigyelhetik más betétes döntéseit, ha a hálózatban össze vannak kapcsolva. Elméletileg a bankroham megelőzésének elégséges feltétele az, ha a második betétes megfigyelheti az első döntését, bármi is legyen az. A kísérlet során azt találjuk, hogy a megfigyelhetőség valóban befolyásolja a bankrohamok kialakulását, és a betétesek döntését jelentősen befolyásolja az, hogy milyen döntést figyelnek meg. Azon betétesek, akik a sor elején vannak és döntéseiket megfigyelik, nagy valószínűséggel nem veszik ki a pénzüket, így összességében kevesebb bankroham alakul ki. Ha a betétesek azt látják, hogy mások kiveszik a pénzüket, akkor nagyobb valószínűséggel alakulnak ki bankrohamok

Would depositors pay to show that they do not withdraw? Theory and experiment

In a Diamond–Dybvig type model of fnancial intermediation, we allow depositors to announce at a positive cost to subsequent depositors that they keep their funds deposited in the bank. Theoretically, the mere availability of public announcements (and not its use) ensures that no bank run is the unique equilibrium outcome. Multiple equilibria—including bank run—exist without such public announcements. We test the theoretical results in the lab and fnd a widespread use of announcements, which we interpret as an attempt to coordinate on the no bank run outcome. Withdrawal rates in general are lower in information sets that contain announcement

A Diamond-Dybvig Model Without Bank Run: the Power of Signaling

This paper introduces the possibility of signaling into a finite-depositor version of the Diamond-Dybvig model. More precisely, the decision to keep the funds in the bank is assumed to be unobservable,but depositors are allowed to make it observable by signaling, at a cost. Depositors decide consecutively whether to withdraw their funds or continue holding balances in the bank, and they choose if they want to signal the latter decision. If the cost of signaling is moderate, then bank runs do not occur. Moreover,no signals are made, so the unconstrained-efficient allocation is implemented without any costs.bank run; sequential game; signaling; iterated deletion of strictly dominated strategies; coordination.

Equilibrium Bank Runs

We analyze a banking system in which the class of feasible deposit contracts, or mechanisms, is broad. The mechanisms must satisfy a sequential service constraint, but partial or full suspension of convertibility is allowed. Consumers must be willing to deposit, ex ante. We show, by examples, that under the so-called "optimal contract," the post-deposit game can have a run equilibrium. Given a "propensity" to run, triggered by sunspots, the optimal contract for the full pre-deposit game can be consistent with runs that occur with positive probability. Thus, the Diamond-Dybvig framework can explain bank runs, as emerging in equilibrium under the optimal deposit contract.

On the Existence of Equilibrium Bank Runs in a Diamond-Dybvig Environment

In a version of the Diamond and Dybvig (1983) model with aggregate uncertainty, we show that there exists an equilibrium with the following properties: all consumers deposit at the bank, all patient consumers wait for the last period to withdraw, and the bank fails with strictly positive probability. Furthermore, we show that the probability of a bank failure remains bounded away from zero as the number of consumers increases. We interpret such an equilibrium as reflecting a bank run, defined as an episode in which a large number of people withdraw their deposits from a bank, forcing it to fail. Our results show that we can have equilibrium bank runs with consumers poorly informed about the true state of nature, a sequential service constraint, an infinite marginal utility of consumption at zero, and without consumers' panic and sunspots. We therefore think that aggregate risk in Diamond-Dybvig-like environments can be an important element to explain bank runs.Bank runs, aggregate uncertainty

Bank Runs Without Sunspots

The literature on bank runs reduces all coordination mechanisms triggering attacks on banks to exogenous sunspots. We present a general equilibrium version of these models where the uncertainty faced by depositors is modeled explicitly, such that bank runs arise as optimal equilibrium outcomes corresponding to Bayesian coordination games played by rational agents before depositing. Differentials in information sets between the bank and its depositors lead to rational self-contained equilibrium runs. The coexistence of different beliefs in equilibrium jointly with the self-fulfilling nature of the attacks follow from Adam Smith's invisible hand principle. The runs obtained do not violate the revelation principle.La literatura sobre pánicos bancarios reduce todo mecanismo de coordinación que de lugar a los ataques a puntos solares exógenos. Presentamos una versión de equilibrio general de dichos modelos en la cual la incertidumbre a la que los agentes económicos se hallan sujetos es modelizada de forma explícita, de manera que los pánicos surgen como resultados óptimos de equilibrio correspondientes a juegos de coordinación Bayesianos jugados por agentes racionales antes de depositar sus fondos en el banco. Diferencias en los conjuntos de información entre el banco y sus clientes dan lugar a pánicos racionales autocontenidos en equilibrio. La coexistencia de diversas creencias probabilísticas en equilibrio, así como la naturaleza auto-contenida de los ataques, derivan del principio de la mano invisible de Adam Smith. Los pánicos obtenidos no violan el principio de revelación.Bank runs, Self-contained attacks, Bayesian coordination games, Revelation principle, Invisible hand principle, Pánicos bancarios, Ataques autocontenidos, Juegos de coordinación Bayesianos, Principio de revelación, Principios de la mano invisible.

Banking Policy without Commitment: Suspension of Convertibility Taken Seriously

We study banking policy credibility in a variant of the Diamond and Dybvig (JPE, 1983) model. By committing to temporarily close banks during a run, suspending the convertibility of deposits into currency, the banking authority can eliminate the possibility of a bank run as an equilibrium outcome. Without commitment, however, if a run were to actually occur it may not be optimal for the authority to keep its promise to suspend convertibility. In other words, the threat of suspension may not be credible. We derive conditions under which a credible suspension scheme can be used to rule out bank runs and conditions under which it cannot. In the latter case, bank runs can occur even when there is no uncertainty about aggregate liquidity demand. We relate the analysis to events in Argentina in 2001, when a system-wide suspension of convertibility was declared but only partially enforcedOptimal Policy, Credibility, Time Consistency, Bank Runs