Knowledge that Transforms

We develop a nonparametric specification test for continuous-time models using the transition density. Using a data transform and correcting for the boundary bias of kernel estimators, our test is robust to serial dependence in data and provides excellent finite sample performance. Besides univariate diffusion models, our test is applicable to a wide variety of continuous-time and discrete-time dynamic models, including time-inhomogeneous diffusion, GARCH, stochastic volatility, regime-switching, jump-diffusion, and multivariate diffusion models. A class of separate inference procedures is also proposed to help gauge possible sources of model mis-specification. We strongly reject a variety of univariate diffusion models for daily Eurodollar spot rates and some popular multivariate affine term structure models for monthly U.S. Treasury yields.

Responding to a September 2002 regulatory enforcement, the Island electronic communications network stopped displaying its limit order book in the three most active exchange-traded funds (ETFs) where it was the dominant venue. Island's share of trading activity and price discovery fell, fragmenting the market. ETF prices adjust more slowly when Island goes dark, and there is substantial price discovery movement from ETFs to the futures market. Trading costs increase on Island and decrease off Island, with higher trading costs overall. When Island later redisplays its orders, market quality improves, with transparency and the reduction in fragmentation both playing important roles.

This article uses unique data from the London Stock Exchange to examine how trader anonymity and market liquidity affect dealers' decisions about where to place interdealer trades. During our sample period, dealers could trade with each other in the direct, nonanonymous public market or use one of four anonymous brokered trading systems. Surprisingly, we find that adverse selection is less prevalent in the anonymous brokered markets. We show that this pattern can be explained by the way dealers "price" the adverse selection risk inherent in trading with other dealers. We also relate our findings to recent changes in dealer markets.

Britten-Jones and Neuberger (2000) derived a model-free implied volatility under the diffusion assumption. In this article, we extend their model-free implied volatility to asset price processes with jumps and develop a simple method for implementing it using observed option prices. In addition, we perform a direct test of the informational efficiency of the option market using the model-free implied volatility. Our results from the Standard & Poor's 500 index (SPX) options suggest that the model-free implied volatility subsumes all information contained in the Black-Scholes (B-S) implied volatility and past realized volatility and is a more efficient forecast for future realized volatility.

We examine the optimal dynamic portfolio decisions for investors who acquire housing services from either renting or owning a house. Our results show that when indifferent between owning and renting, investors owning a house hold a lower equity proportion in their net worth (bonds, stocks, and home equity), reflecting the substitution effect, yet hold a higher equity proportion in their liquid portfolios (bonds and stocks), reflecting the diversification effect. Furthermore, following the suboptimal policy of always renting leads investors to overweigh in stocks, while following the suboptimal policy of always owning a house causes investors to underweigh in stocks.

We present a simulation-based method for solving discrete-time portfolio choice problems involving non-standard preferences, a large number of assets with arbitrary return distribution, and, most importantly, a large number of state variables with potentially path-dependent or non-stationary dynamics. The method is flexible enough to accommodate intermediate consumption, portfolio constraints, parameter and model uncertainty, and learning. We first establish the properties of the method for the portfolio choice between a stock index and cash when the stock returns are either iid or predictable by the dividend yield. We then explore the problem of an investor who takes into account the predictability of returns but is uncertain about the parameters of the data generating process. The investor chooses the portfolio anticipating that future data realizations will contain useful information to learn about the true parameter values.

We estimate parameters of standard stock selection and market timing models using daily mutual fund returns and quarterly measurement periods. We then rank funds quarterly by abnormal return and measure the performance of each decile the following quarter. The average abnormal return of the top decile in the post-ranking quarter is 39 basis points. The post-ranking abnormal return disappears when funds are evaluated over longer periods. These results suggest that superior performance is a short-lived phenomenon that is observable only when funds are evaluated several times a year.

The proposed model, by incorporating both (1) banker screening of new issues and (2) costly evaluation by investors, is the first to admit endogenous double-sided information production. It demonstrates a nontrivial link between these two sides: the banker wishes to structure a sale conducive to investor research because selling to an uninformed pool would result in his own shirking. One application of this paradigm indicates that, contrary to the findings of most IPO models, larger investor pools are not always better. This result resolves the "participation restriction puzzle" of why bankers do not open sales to all bidders even when doing so would maximize competition and reduce underpricing.

We argue that competition between dealers in a classic dealer market is intertemporal: A trader identifies a particular dealer and negotiates a final price with only the intertemporal threat to switch dealers imposing pricing discipline on the dealer. In this kind of market structure, we show that dealers will offer greater price improvement to more regular customers, and, in turn, these customers optimally choose to submit larger orders. Hence, price improvement and trade size should be negatively correlated in a dealer market. We confirm our model's predictions using unique data from the London Stock Exchange during 1991.

Cross-country bank lending appears to be subject to market imperfections leading to persistent interest rate differentials. In a model where banks need to cope with liquidity shocks by borrowing or by liquidating assets, we study the scope for international interbank market integration with unsecured lending when cross-country information is noisy. We find that an equilibrium with integrated markets need not always exist, and that it may coexist with one characterized by segmentation. A repo market reduces interest rate spreads and improves upon the segmentation equilibrium. However, it may destroy the unsecured integrated equilibrium.