We analyze the optimal financing of investment projects when managers must exert unobservable effort and can also switch to less profitable riskier ventures. Optimal financial contracts can be implemented by a combination of debt and equity when the risk‐shifting problem is the most severe while stock options are also needed when the effort problem is the most severe. Worsening of the moral hazard problems leads to decreases in investment and output at the macroeconomic level. Moreover, aggregate leverage decreases with the risk‐shifting problem and increases with the effort problem.

Abstract In order to share risk, protection buyers trade derivatives with protection sellers. Protection sellers’ actions affect the riskiness of their assets, which can create counterparty risk. Because these actions are unobservable, moral hazard limits risk sharing. To mitigate this problem, privately optimal derivative contracts involve variation margins. When margins are called, protection sellers must liquidate some assets, depressing asset prices. This tightens the incentive constraints of other protection sellers and reduces their ability to provide insurance. Despite this fire-sale externality, equilibrium is information-constrained efficient. Investors, who benefit from buying assets at fire-sale prices, optimally supply insurance against the risk of fire sales.

[We analyze theoretically and empirically the implications of information asymmetry for equilibrium asset pricing and portfolio choice. In our partially revealing dynamic rational expectations equilibrium, portfolio separation fails, and indexing is not optimal. We show how uninformed investors should structure their portfolios, using the information contained in prices to cope with winner's curse problems. We implement empirically this pricecontingent portfolio strategy. Consistent with our theory, the strategy outperforms economically and statistically the index. While momentum can arise in the model, in the data, the momentum strategy does not outperform the price-contingent strategy, as predicted by the theory.]

We study the dynamics of an innovative industry in which agents learn about the likelihood of negative shocks. Managers can exert risk prevention effort to mitigate the consequences of shocks. If no shock occurs, confidence improves, attracting managers to the innovative sector. But, when confidence becomes high, inefficient managers exerting low risk-prevention effort also enter. This stimulates growth, while reducing risk prevention. The longer the boom, the larger the losses if a shock occurs. Although these dynamics arise in the first-best, asymmetric information generates excessive entry of inefficient managers, earning informational rents, inflating the innovative sector, and increasing its vulnerability.

ABSTRACT Derivatives activity, motivated by risk‐sharing, can breed risk‐taking. Bad news about the risk of an asset underlying a derivative increases protection sellers' expected liability and undermines their risk‐prevention incentives. This limits risk‐sharing, creates endogenous counterparty risk, and can lead to contagion from news about the hedged risk to the balance sheet of protection sellers. Margin calls after bad news can improve protection sellers' incentives and in turn enhance risk‐sharing. Central clearing can provide insurance against counterparty risk but must be designed to preserve risk‐prevention incentives.

ABSTRACT As a centralized, computerized, limit order market, the Paris Bourse is particularly appropriate for studying the interaction between the order book and order flow. Descriptive methods capture the richness of the data and distinctive aspects of the market structure. Order flow is concentrated near the quote, while the depth of the book is somewhat larger at nearby valuations. We analyze the supply and demand of liquidity. For example, thin books elicit orders and thick books result in trades. To gain price and time priority, investors quickly place orders within the quotes when the depth at the quotes or the spread is large. Consistent with information effects, downward (upward) shifts in both bid and ask quotes occur after large sales (purchases).

As a centralized, computerized, limit order market, the Paris Bourse is particularly appropriate for studying the interaction between the order book and order flow. Descriptive methods capture the richness of the data and distinctive aspects of the market structure. Order flow is concentrated near the quote, while the depth of the book is somewhat larger at nearby valuations. We analyze the supply and demand of liquidity. For example, thin books elicit orders and thick books result in trades. To gain price and time priority, investors quickly place orders within the quotes when the depth at the quotes or the spread is large. Consistent with information effects, downward (upward) shifts in both bid and ask quotes occur after large sales (purchases).

Before the opening of the Paris Bourse, traders place orders and indicative prices are set. This offers a laboratory to study empirically the tâtonnement process through which markets discover equilibrium prices. Since preopening orders can be revised or canceled before the opening, indicative prices could be noise. We test this against the hypothesis that preopening prices reflect learning.Early in the preopening the noise hypothesis is not rejected. As the opening gets closer, the informational content and efficiency of prices increase and the learning hypothesis is not rejected. We also propose a GMM‐based estimate of the speed of learning.

We study how securities and issuance mechanisms can be designed to mitigate the adverse impact of market imperfections on liquidity. In our model, asset owners seek to obtain liquidity by selling claims contingent on privately observed future cash-flows. Liquidity suppliers can be competitive or strategic. In the optimal trading mechanism associated with an arbitrary given security, issuers with low cash-flows sell their entire holdings of the security, while issuers with high cash-flows are typically excluded from trade. By designing the security optimally, issuers can avoid exclusion altogether. We show that the optimal security is debt. Because of its low informational sensitivity, debt mitigates the adverse selection problem. Furthermore, by pooling all issuers with high cash-flows, debt also reduces the ability of a monopolistic liquidity supplier to exclude them from trade in order to better extract rents from issuers with lower cash-flows.

Speculators buy an asset hoping to sell it later to investors with higher private valuations. If agents are uncertain about the distribution of private valuations and about the beliefs of others about this distribution, a beauty contest with an infinite hierarchy of beliefs arises. Under Harsanyi's assumption of a common prior the infinite beliefs hierarchy is readily solved using Bayes' law. This paper shows that common knowledge of the “beliefs formation rule,” mapping the private valuation of each agent into his first-order belief, also simplifies the beliefs hierarchy while allowing for disagreement among agents. We analyse the resulting speculation in a stylized asset market. Several statistics, computed only from readily observable quote, return and volume data, are evaluated in terms of their power to discriminate between genuine disagreement and the Harsanyian case. Only statistics that relate volume and volatility, or volume and changes in best offers, have the necessary discriminatory power.