Knowledge that Transforms

Implied risk aversion estimates reported in the literature are strongly U-shaped. This article explores different potential explanations for these “smile” patterns: (i) preference aggregation, both with and without stochastic volatility and jumps in returns, (ii) misestimation of investors’ beliefs caused by stochastic volatility, jumps, or a Peso problem, and (iii) heterogeneous beliefs. The results reveal that preference aggregation and misestimation of investors’ beliefs caused by stochastic volatility and jumps are unlikely to be the explanation for the smile. Although a Peso problem can account for the smile, the required probability of a market crash is unrealistically large. Heterogeneous beliefs cause sizable distortions in implied risk aversion, but the degree of heterogeneity required to explain the smile is implausibly large.

Over the years numerous portfolio performance measures have been proposed. In general they are designed to capture some particular enhancement that might result from active management. However, if a principal uses a measure to judge an agent, then the agent has an incentive to game the measure. Our paper sh

We analyze the optimal investment decisions of heterogeneous firms in a competitive, uncertain environment, characterizing firms' investment strategies explicitly and deriving closed-form solutions for firm value. Real option premia remain significant, and are even unmitigated relative to the standard partial-equilibrium model when both are calibrated to observables. Firms consequently delay investment, choosing not to undertake some positive NPV projects. We compare competitive behavior to that of a strategic monopolist, and quantify the welfare loss associated with monopoly. Finally, the model predicts business cycle dependence on firm returns, with returns negatively skewed during industry expansions but positively skewed in industry recessions.

We examine whether spin-offs or divestitures cause improvements in conglomerate investment efficiency. At issue are endogeneity of these restructuring decisions and correct measurement of investment efficiency. Endogeneity is a problem because the factors that induce firms to spin off or divest divisions may also improve investment efficiency; measurement error is a problem because efficiency measures employ Tobin’s q as a noisy proxy for investment opportunities. We find important differences between firms that divest or spin off and a control sample. After accounting for these differences and for measurement error in q, we find no evidence of improvements in investment efficiency.

This article examines underpricing of initial public offerings (IPOs) and seasoned offerings in the corporate bond market. We investigate whether underpricing represents a solution to an information problem or a liquidity problem. We find that underpricing occurs with both IPOs and seasoned offerings and is highest among riskier, unknown firms. Our evidence suggests that information problems drive underpricing, with support for both the bookbuilding view of underpricing and the asymmetric information theory. We do not find evidence in favor of the Rock model of underpricing or any evidence that illiquidity causes underpricing. , Oxford University Press.

International audience

The Black-Scholes-Merton option valuation method involves deriving and solving a partial differential equation (PDE). But this method can generate multiple values for an option. We provide new solutions for the Cox-Ingersoll-Ross (CIR) term structure model, the constant elasticity of variance (CEV) model, and the Heston stochastic volatility model. Multiple solutions reflect asset pricing bubbles, dominated investments, and (possibly infeasible) arbitrages. We provide conditions to rule out bubbles on underlying prices. If they are not satisfied, put-call parity might not hold, American calls have no optimal exercise policy, and lookback calls have infinite value. We clarify a longstanding conjecture of Cox, Ingersoll, and Ross. (JEL G12 and G13)

We address a fundamental question in relationship banking: why do banks that make relationship loans finance themselves primarily with core deposits and when would it be optimal to finance such loans with purchased money? We show that not only are relationship loans informationally opaque and illiquid, but they also require the relationship between the bank and the borrower to endure in order for the bank to add value. However, the informational opacity of relationship loans gives rise to endogenous withdrawal risk that makes the bank fragile. Core deposits are an attractive funding source for such loans because the bank provides liquidity services to core depositors and this diminishes the likelihood of premature deposit withdrawal, thereby facilitating the continuity of relationship loans. That is, we show that banks will wish to match the highest value-added liabilities with the highest value-added loans and that doing so simultaneously minimizes the bank's fragility owing to withdrawal risk and maximizes the value the bank adds in relationship lending. We also examine the impact of interbank competition on the bank's asset-liability matching and extract numerous testable predictions.

This article proposes a test for the cost-based explanation of nonparticipation, by estimating a lower bound to the forgone gains of incomplete portfolios; these are in turn a lower bound to the costs that could rationalize nonparticipation in financial markets: high bounds would imply implausibly high costs. Assuming isoelastic utility and a relative risk aversion of three or less, for the stock market I estimate an average lower bound of between 0.7 and 3.3 percent of consumption. Since total annual (observable plus unobservable) participation costs are likely to exceed these bounds, the cost-based explanation is not rejected by this test. , Oxford University Press.

Agency problems limit firms' access to capital markets, curbing investment. Firms and investors seek contractual ways to mitigate these problems. What are the implications for investment? We present a theory of a firm's investment dynamics in the presence of agency problems and optimal long-term financial contracts. We derive results relating firms' investment decisions, current and past cash flows, firm size, capital structure, and dividends. Among the results, optimal investment is increasing in current and past cash flow; and optimal investment is positively serially correlated over time (after controlling for investment opportunities). These results hold for a range of agency problems. (JEL G30, G31, G32, G35, D82, D86, D92) Copyright 2007, Oxford University Press.