Financial Engineering

When a boom ends, the downturn is generally sharp and short. When growth resumes, the boom is more gradual. Our explanation rests on learning about productivity. When agents believe productivity is high, they work, invest, and produce more. More production generates higher precision information. When the boom ends, precise estimates of the slowdown prompt decisive reactions: Investment and labor fall sharply. When growth resumes, low production yields noisy estimates of recovery. Noise impedes learning, slows recovery, and makes booms more gradual than downturns.

The stochastic differential equations for affine jump diffusion models do not yield exact solutions that can be directly simulated. Discretization methods can be used for simulating security prices under these models. However, discretization introduces bias into the simulation results and a large number of time steps may be needed to reduce the discretization bias to an acceptable level. This paper suggests a method for the exact simulation of the stock price and variance under Heston's stochastic volatility model and other affine jump diffusion processes.

*Winner, Distinguished Paper award of the Smith-Breeden Prize.

Recent empirical research documents that the strong short-term relationship between U.S. monetary aggregates on one side and inflation and real output on the other has mostly disappeared since the early 1980s. Using the direct estimate of flows of U.S. dollars abroad we find that domestic money (currency corrected for the foreign holdings of dollars) contains valuable information about future movements of U.S. inflation and real output.

This paper compares methods for computing the distribution of loss from defaults in a credit portfolio. The methods are applied in the Gaussian copula framework for credit risk and take advantage of the conditional independence of defaults in this framework. As a benchmark we use vanilla Monte Carlo simulation to estimate the tail probabilities of the total losses of the credit portfolio. The first method to be compared is a recursive algorithm to obtain the exact distribution of the total loss of the portfolio, conditional on observed values for the systematic risk factors.

Multidivisional firms frequently rely on external market prices in order to value internal transactions across profit centers. This paper examines the transfer pricing problem in a setting in which an upstream division has monopoly power in selling a proprietary component both to a downstream division within the same firm and to external customers. When internal transfers are valued at the prevailing market price, the resulting transactions are distorted by double marginalization.

We develop a model of lending and borrowing in markets where the lender has no access to physical collateral and where the borrower is heavily capital constrained. Our model of micro loans, which incorporates a) the absence of access to physical collateral, b) peer monitoring, c) threat of punishment upon default, and d) costly monitoring by lenders is used to determine the equilibrium borrowing rates. Monitoring by lenders is shown to be critical for an equilibrium to exist in our model if the maturity of the loan is too long.

Friedman's contribution to the consumption literature goes well beyond the seminal permanent-income hypothesis. He conjectured that the marginal propensity to consume out of financial wealth shall be larger than out of "human wealth," the present discounted value of future labor income. I present an explicitly solved model to deliver this widely-noted consumption property by specifying that the conditional variance of changes in income increases with its level.