Uzi Yaari

The Efficacy of Term Structure Estimation Technique: A Monte Carlo Study

The term structure of default-free interest rates is not directly observable in a market where government obligations of various maturities bear coupons at different rates, and where ordinary income and capital gains are subject to unknown and varying effective tax rates. Accurate knowledge of the term structure of spot rates and underlying forward rates is essential for financial research and practice. There are various methods for empirically estimating forward rates and numerous studies that test the accuracy of those methods. Yet, that accuracy cannot be ascertained without knowledge of the true underlying forward rates or the error distribution of those rates. With an unknown error distribution, the statistical estimation of forward rates may be biased. This study offers two innovations designed to improve term structure estimation. First, we use Monte Carlo simulation to generate data with known parameters, which are free of unknown biases. The synthetic data are used to test and compare the accuracy of competing methods in estimating the known forward rates. Second, the knowledge obtained from such tests should enable researchers and practitioners to select the best method for estimating unknown forward rates from empirical data. In contrast, estimation methods are currently selected based on their power to explain variations in bond prices. We provide evidence that the two procedures are poor substitutes. While a variety of estimation methods are good at explaining variations in bond prices, our findings reveal considerable differences among widely known methods in their ability to estimate forward rates.

Initial Public Offering Discount and Competition

Lacking examples of initial public offering (IPO) mechanisms that are open to the public and priced competitively, previous studies could not determine what size discount, if any, is economically efficient. We compare two pricing regimes on the Tel Aviv Stock Exchange: an investor‐driven Dutch auction limited by a binding maximum price replaced by one that is free of that constraint. Our evidence shows that rationing and herding disappear, improving the access of uninformed investors to strong issues and alleviating their exposure to losses attached to weak issues; pricing quality increases by the elimination of the underpricing bias, decreased price dispersion, and increased price sensitivity to IPO‐unique factors. Underwriter services do not deteriorate but garner moderately higher fees, apparently to compensate for a higher risk. Consistently, there is no deterioration in IPO efficiency as a screen from weak issues. Our evidence does not support the view that underpricing is competitive or efficient.

Pecking order as a dynamic leverage theory

Static tradeoff theories, which do not explicitly treat the impact of transaction costs, do not explain the policy of asymmetry between frequent small debt transactions and infrequent large equity transactions. Nor do these theories explain why the debt ratio is allowed to wander a considerable distance from its alleged static optimum, or how much of a distance should be tolerated. We offer a class of diffusion models that mimic this behaviour in a stochastic-dynamic framework and are designed to optimize a financing strategy using any static tradeoff theory as input. The models developed reveal the determinants of the size and frequency of equity transactions and the range of values over which leverage variations are tolerated in four generic scenarios. They also yield a new formulation of the cost of capital that recognizes stochastic transaction costs and a penalty for deviation from any static-optimal leverage. Our class of models augments the pecking order theory, provides a flexible quantitative framework for its implementation as a decision tool, and facilitates the formulation of additional hypotheses for its empirical validation. Symmetrically, our results show the importance of dynamic factors in designing and interpreting empirical tests of static tradeoff theories. The results presented have important implications for the role played by static tradeoff theories in a stochastic-dynamic framework. One such implication is that the static-optimal leverage has no direct effect on the firms leverage policy in this setting. The target leverage for refinancing transactions is different from the static-optimal leverage, and the mean leverage is generally different from both. As a consequence, the latter cannot be used to estimate the former. Another implication is that even when the mean leverage equals the static optimum, mean reversion is not an optimal behaviour and therefore not a legitimate test for the existence of a static tradeoff in a dynamic context. Still another implication is that wide variations in leverage ratios cannot be interpreted as evidence of leverage indifference. It follows that the pecking order theory is consistent with static tradeoff theories and does not require the assumption of leverage indifference.

Financial leverage strategy with transaction costs

This paper offers a class of diffusion models that mimic the firms pecking order behaviour and are designed to optimize an intertemporal leverage strategy in the presence of refinancing transaction costs. The proposed class of models is compatible with traditional static tradeoff theories and can be used to recast those theories in a dynamic framework by superimposing refinancing costs. We derive analytical expressions for the parameters of an optimal leverage strategy with exogenous refinancing limits, including the minimum cost of capital in a stochastic dynamic framework with transaction costs, the target values to which the leverage should be readjusted when the limits are reached, and the mean leverage implied by the optimal strategy. Our class of models enriches the pecking order theory and provides a quantitative framework for its implementation as a decision tool. It also provides additional hypotheses for empirical validation of that theory. Symmetrically, our results show the importance of dynamic factors in designing and interpreting empirical tests of static tradeoff theories.

Trading Frequency and the Efficiency of Price Discovery in a Non-Dealer Market

The increasing popularity of non-dealer security markets that offer automated, computer-based, continuous trading reflects a presumption that institutionally-set trading sessions are economically obsolete. This theoretical paper investigates the effect of the trading frequency, a key feature of the trading mechanism, on the efficiency of price discovery in a non-dealer market. By tracing the market pricing error to the correlation structures of arriving information and pricing errors of individual traders, the effect of diverging expectations on error-based and overall return volatility is isolated. The analysis reveals that, due to a portfolio effect, an increase in the trading time interval has contradictory effects on the portion of return volatility stemming from pricing errors. The greater accumulation of information increases error-based return volatility, but the greater volume and number of traders per session have the opposite effect. The net effect on overall return volatility can go either way. It is found that the return volatility of heavily traded securities is likely to be minimized under continuous trading, but that of thinly traded securities may be minimized under discrete trading at moderate time intervals. The latter is more likely to occur the greater is the divergence of expectations among traders. These findings challenge the presumption that automated continuous trading in a non-dealer market is more efficient than discrete trading for all securities, regardless of trading volume. The findings are applicable to all economies, but have special importance for developing countries where typically a single market is dominated by small issues and a low volume of trade. As a by-product of the analysis, it is shown how to correct the biased estimate of inter-session price volatility when observations are less frequent than the trading sessions themselves.

Share values, inflation, and escalating tax rates

The interaction of inflation with a progressive tax system has been known to cause tax rates, and thus tax liabilities, to escalate with nominal income. Often blamed for having undesirable effects on investment and wealth, this feature of modern tax systems has not received formal treatment in the literature. The partial-equilibrium valuation model presented is used to examine the impact of escalating tax rates on the value of corporate equity. It is shown that the combination of moderate inflation and mildly progressive tax rates may have a substantial adverse effect on share values, an effect sharply increasing with the firms real growth rate. A by-product of the analysis is a partial equilibrium explanation for the apparent conflict between the Fisherian hypothesis and the commonly observed inverse relationship between the rate of inflation and the deflated value of stock prices. To the extent that occasional adjustments of the tax schedule do not prevent taxpayers from being pushed toward higher tax brackets, these results suggest a sizable potential benefit from full indexation of tax rates in an economy suffering from chronic inflation. These results also confirm the belief that failure to do so is especially harmful to economic growth.

Market Insurance Versus Self Insurance: The Tax-Differential Treatment and its Social Cost

Much resources have been expended over the years debating the tax treatment of insurance versus self insurance. This article reviews and analyzes the principal concepts and inconsistencies that have evolved in dealing with the issue of premium tax deductibility. The Internal Revenue Service considers market insurance as the only visible means of risk shifting and therefore the only one worthy of tax deductibility. It is argued that other forms of risk reduction can be equally effective in reducing risk. The social cost associated with the present tax policy that favors market insurance over other forms of pre-loss risk financing are evaluated and depicted. The implicit objective of the article is toshift the debate by refocusing on the question of an appropriate tax policy concerning risk financing, one that maximizes social welfare.

Unions, Default Risk, and Pension Underfunding

An explanation is provided for the following seemingly unrelated pieces of evidence concerning unions and pension plans in the United States: 1) The pension wealth of union members is greater than that of other workers, but 2) union pension plans are more often underfunded and 3) more likely to be terminated by default.

Beta Estimation with Stock Return Outliers: The Case of U.S. Pharmaceutical Companies

Efficient estimation of the equity cost of public corporations is an essential component of computing the required rate of return of real investment projects, and therefore the basis for a rational investment policy. The accepted methodology relies on the CAPM model to define the return risk premium, and the OLS method to estimate the beta risk coefficient required for calculating the premium. This study challenges the use of the OLS method for this task by demonstrating its vulnerability to the impact of stock return outliers caused by large, unpredictable, company-specific events. That impact is verified on a sample of U.S. pharmaceutical companies by comparing the OLS estimation performance with that of our proposed method based on Huber’s Robust M (HRM) estimator, a related statistical method that follows a mixed return model identifying regular and outlier return components. Using the HRM-estimated beta as a benchmark, we demonstrate that (1) outliers can substantially bias the OLS beta, (2) the bias is negatively correlated with company size, and (3) the size of the bias is often moderated but not eliminated by extending the estimation period. The latter finding suggests that a robust method like HRM is preferable where estimators ought to represent the behavior of the majority of historical data despite the presence of outliers. The risk of trusting the OLS beta is especially high when estimation must rely on a small sample.

International Hedge of Fixed-Income Contracts

The fixed–income literature is concerned with hedging strategies for controlling the interest rate risk of assets and liabilities held domestically in a single currency. That there is little research dedicated to international immunization may reflect a view that companies and financial institutions dealing internationally need only replicate a single–currency hedging strategy in each country. The authors argue that separate immunization in each country is overly restrictive and may be costly to execute. Instead, they propose a less restrictive strategy treating the assets and liabilities held across currencies as portfolios, and matching the duration of those portfolios. Their immunization strategy should directly reduce the cost of international hedging against interest risk, and indirectly reduce the cost of hedging against currency risk. Simulation results suggest that the proposed strategy should be at least as effective as well as cheaper to implement.