Testing for Unit Roots with Breaks: Evidence on the Great Crash and the Unit Root Hypothesis Reconsidered

Nelson and Plosser (1982), in a classic paper, failed to find strong evidence against the null hypothesis of a generating process with a unit autoregressive root for thirteen US macroeconomic time series. Perron (1989) claimed that such evidence was available for a majority of these series if the alternative hypothesis was of trend stationarity with a break in 1929. Zivot and Andrews (1992) treated the break date as endogenous, then finding strong evidence agcainst the null for a minority of these series. Our own analysis extends theirs by permitting a break under the null as well as the alternative hypothesis, and allowing for the sequential nature of the testing. Our empirical findings complete the circle. We find no strong evidence against the unit root hypothesis for any of the thirteen Nelson–Plosser series.     

SUPPLY CHAIN INFORMATION SHARING IN A VENDOR MANAGED INVENTORY PARTNERSHIP

Vendor Managed Inventory (VMI) involves the vendor making the replenishment decision for products supplied to a customer based on various inventory and supply chain policies. Information sharing between supply chain members is required in VMI. Sometimes VMI decisions are delayed and/or the information shared is inaccurate. This research examines the effects of information delay and accuracy, and the sharing of sales and forecast information in a VMI environment facing stationary and nonstationary demand. The simulation experiments show the impact of information delay, information inaccuracy, and information sharing on a variety of performance measures, including inventory levels and fill rates.     

CATALOG RETAILER IN‐STOCK PERFORMANCE: AN ASSESSMENT OF CUSTOMER SERVICE LEVELS

The purpose of this article is to study the level of “in‐stock” customer service performance being offered in the catalog channel of distribution. The article provides benchmark information for the catalog industry. More importantly, the article serves as one test of the effectiveness of the modern supply chain, where the expectation is for near perfect orders. Customer service levels are studied by using an empirical observation methodology in which catalog retailer's in‐stock performance was measured. Comparisons are made across item type, season, retailer type, and days from catalog receipt. Overall, items were out‐of‐stock during 15.9% of all checkpoints, compared to an 11.8% stock‐out rate in an earlier study of bricks and mortar retailers.     

Uniform Commercial Policy, Illegal Trade, and the Real Exchange Rate: A Theoretical Analysis

Countries on fixed exchange rates sometimes use uniform tariffcum subsidy (UTCS) schemes as a way of achieving a real depreciationwithout disturbing the nominal exchange rate. A potential drawbackof this policy in relation to an across-the-board devaluationis that a UTCS scheme provides incentives for illegal trade.Using an optimizing model with currency convertibility and illegaltrade. I find that welfare is lower under a UTCS scheme thanunder a corresponding across-the-board devaluation and thatin some cases the real exchange rate actually appreciates inresponse to an increase in the UTCS rate.     

The Relation between Market Values,Earnings Forecasts,and Reported Earnings*

Recently, much of the research into the relation between market values and accounting numbers has used, or at least made reference to, the residual income model (RIM). Two basic types of empirical research have developed. The “historical” type explores the relation between market values and reported accounting numbers, often using the linear dynamics in Ohlson 1995 and Feltham and Ohlson 1995 and 1996. The “forecast” type explores the relation between market value and the present value of the book value of equity, a truncated sequence of residual income forecasts, and an estimate of the terminal value at the truncation date. The analysis in this paper integrates these two approaches. We expand the Feltham and Ohlson 1996 model by including one‐ and two‐period‐ahead residual income forecasts to infer “other” information regarding future revenues from past investments and future growth opportunities. This approach results in a model in which the difference between market value and book value of equity is a function of current residual income, one‐ and two‐period‐ahead residual income, current capital investment, and start‐of‐period operating assets. The existence of both persistence in revenues from current and prior investments and growth in future positive net present value investment opportunities leads us to hypothesize a negative coefficient on the one‐period‐ahead residual income forecast and a positive coefficient on the two‐period‐ahead residual income forecast. Our empirical results strongly support our hypotheses with respect to the forecast coefficients.     

A MULTINOMIAL APPROXIMATION FOR AMERICAN OPTION PRICES IN LÉVY PROCESS MODELS

This paper gives a tree-based method for pricing American options in models where the stock price follows a general exponential Lévy process. A multinomial model for approximating the stock price process, which can be viewed as generalizing the binomial model of Cox, Ross, and Rubinstein (1979) for geometric Brownian motion, is developed. Under mild conditions, it is proved that the stock price process and the prices of American-type options on the stock, calculated from the multinomial model, converge to the corresponding prices under the continuous time Lévy process model. Explicit illustrations are given for the variance gamma model and the normal inverse Gaussian process when the option is an American put, but the procedure is applicable to a much wider class of derivatives including some path-dependent options. Our approach overcomes some practical difficulties that have previously been encountered when the Lévy process has infinite activity.