Lawrence H. Summers

Bio: Lawrence H. Summers is an academic researcher from Harvard University. The author has contributed to research in topics: Investment (macroeconomics) & Unemployment. The author has an hindex of 102, co-authored 285 publications receiving 58555 citations. Previous affiliations of Lawrence H. Summers include The Treasury & National Science Foundation.

Noise Trader Risk in Financial Markets

Abstract: We present a simple overlapping generations model of an asset market in which irrational noise traders with erroneous stochastic beliefs both affect prices and earn higher expected returns. The unpredictability of noise traders' beliefs creates a risk in the price of the asset that deters rational arbitrageurs from aggressively betting against them. As a result, prices can diverge significantly from fundamental values even in the absence of fundamental risk. Moreover, bearing a disproportionate amount of risk that they themselves create enables noise traders to earn a higher expected return than rational investors do. The model sheds light on a number of financial anomalies, including the excess volatility of asset prices, the mean reversion of stock returns, the underpricing of closed-end mutual funds, and the Mehra-Prescott equity premium puzzle.

Positive Feedback Investment Strategies and Destabilizing Rational Speculation

Abstract: Analyses of the role of rational speculators in financial markets usually presume that such investors dampen price fluctuations by trading against liquidity or noise traders This conclusion does not necessarily hold when noise traders follow positive-feedback investment strategies buy when prices rise and sell when prices fall In such cases, it may pay rational speculators to try to jump on the bandwagon early and to purchase ahead of noise trader demand If rational speculators' attempts to jump on the bandwagon early trigger positive-feedback investment strategies, then an increase in the number of forward-looking rational speculators can lead to increased volatility of prices about fundamentals

Positive Feedback Investment Strategies and Destabilizing Rational Speculation

Abstract: Analyses of rational speculation usually presume that it dampens fluctuations caused by "noise" traders. This is not necessarily the case if noise traders follow positivefeedback strategies-buy when prices rise and sell when prices fall. It may pay to jump on the bandwagon and purchase ahead of noise demand. If rational speculators' early buying triggers positive-feedback trading, then an increase in the number of forwardlooking speculators can increase volatility about fundamentals. This model is consistent with a number of empirical observations about the correlation of asset returns, the overreaction of prices to news, price bubbles, and expectations. WHAT EFFECT DO RATIONAL speculators have on asset prices? The standard answer, dating back at least to Friedman (1953), is that rational speculators must stabilize asset prices. Speculators who destabilize asset prices do so by, on average, buying when prices are high and selling when prices are low; such destabilizing speculators are quickly eliminated from the market. By contrast, speculators who earn positive profits do so by trading against the less rational investors who move prices away from fundamentals. Such speculators rationally counter the deviations of prices from fundamentals and so stabilize them. Recent work on noise trading and market efficiency has accepted this argument (Figlewski, 1979; Kyle, 1985; Campbell and Kyle, 1988; DeLong, Shleifer, Summers, and Waldmann, 1987). In this work, risk aversion keeps rational speculators from taking large arbitrage positions, so noise traders can affect prices. Nonetheless, the effect of rational speculators' trades is to move prices in the direction of, even if not all the way to, fundamentals. Rational speculators buck noisedriven price movements and so dampen, but do not eliminate, them. In this paper we present a possibly empirically important exception to this argument, based on the prevalence of positive feedback investors in financial markets. Positive feedback investors are those who buy securities when prices rise and sell when prices fall. Many forms of behavior common in financial markets can be described as positive feedback trading. It can result from extrapolative expectations about prices, or trend chasing. It can also result from stoploss orders, which effectively prompt selling in response to price declines. A

Efficiency wages and the inter-industry wage structure

Abstract: This paper empirically tests and rejects classical competitive theories of wage determination by examining differences in wages for equally skilled workers across industries. Human capital earnings functions are estimated using cross-sectional and longitudinal data from the CPS and QES. The major finding is that the dispersion in wages across industries as measured by the standard deviation in industry wage differentials is substantial. Furthermore, F tests of the joint significance of industry dummy variables are decisively rejected. These differences are very difficult to link to unobserved differences in ability or to compensating differentials for working conditions. Fixed effects models are estimated using two longitudinal data sets to control for constant, unmeasured worker characteristics that might bias cross-sectional estimates. Because measurement error is a serious problem in looking at workers who report changing industries, we use estimates of industry classification error rates to adjust the longitudinal results. In the fixed effects analysis, the industry wage differentials are sizable and are very similar to the cross-sectional estimates. In addition, the fixed effects estimates are robust under a variety of assumptions about classification errors and are similar using both data sets. These findings cast doubt on explanations of industry wage differentials based on unmeasured ability. Additional analysis finds that the industry wage structure is highly correlated for workers in small and large firms, in different regions of the U.S., and with varying job tenures. Finally, evidence is presented demonstrating that turnover has a negative relationship with industry wage differentials. These findings suggest that workers in high wage industries receive noncompetitive rents.

Hysteresis and the European Unemployment Problem

Abstract: European unemployment has been steadily increasing for the last 15 years and isexpected to remain very high for many years to come. In this paper, we argue thatthis fact implies that shocks have much more persistent effects on unemployment thanstandard theories can possibly explain. We develop a theory which can explain suchpersistence, and which is based on the distinction between insiders and outsiders inwage bargaining. We argue that if wages are largely set by bargaining betweeninsiders and firms, shocks which affect actual unemployment tend also to affectequilibrium unemployment. We then confront the theory to both the detailed facts ofthe European situation as well as to earlier periods of high persistent unemploymentsuch as the Great Depression in the US.

Bounds testing approaches to the analysis of level relationships

Abstract: This paper develops a new approach to the problem of testing the existence of a level relationship between a dependent variable and a set of regressors, when it is not known with certainty whether the underlying regressors are trend- or first-difference stationary. The proposed tests are based on standard F- and t-statistics used to test the significance of the lagged levels of the variables in a univariate equilibrium correction mechanism. The asymptotic distributions of these statistics are non-standard under the null hypothesis that there exists no level relationship, irrespective of whether the regressors are I(0) or I(1). Two sets of asymptotic critical values are provided: one when all regressors are purely I(1) and the other if they are all purely I(0). These two sets of critical values provide a band covering all possible classifications of the regressors into purely I(0), purely I(1) or mutually cointegrated. Accordingly, various bounds testing procedures are proposed. It is shown that the proposed tests are consistent, and their asymptotic distribution under the null and suitably defined local alternatives are derived. The empirical relevance of the bounds procedures is demonstrated by a re-examination of the earnings equation included in the UK Treasury macroeconometric model. Copyright © 2001 John Wiley & Sons, Ltd.

A Survey of Corporate Governance

Abstract: This paper surveys research on corporate governance, with special attention to the importance of legal protection of investors and of ownership concentration in corporate governance systems around the world.

A Survey of Corporate Governance

Abstract: This article surveys research on corporate governance, with special attention to the importance of legal protection of investors and of ownership concentration in corporate governance systems around the world. CORPORATE GOVERNANCE DEALS WITH the ways in which suppliers of finance to corporations assure themselves of getting a return on their investment. How do the suppliers of finance get managers to return some of the profits to them? How do they make sure that managers do not steal the capital they supply or invest it in bad projects? How do suppliers of finance control managers? At first glance, it is not entirely obvious why the suppliers of capital get anything back. After all, they part with their money, and have little to contribute to the enterprise afterward. The professional managers or entrepreneurs who run the firms might as well abscond with the money. Although they sometimes do, usually they do not. Most advanced market economies have solved the problem of corporate governance at least reasonably well, in that they have assured the flows of enormous amounts of capital to firms, and actual repatriation of profits to the providers of finance. But this does not imply that they have solved the corporate governance problem perfectly, or that the corporate governance mechanisms cannot be improved. In fact, the subject of corporate governance is of enormous practical impor

Returns to Buying Winners and Selling Losers: Implications for Stock Market Efficiency

Abstract: This paper documents that strategies which buy stocks that have performed well in the past and sell stocks that have performed poorly in the past generate significant positive returns over 3- to 12-month holding periods. We find that the profitability of these strategies are not due to their systematic risk or to delayed stock price reactions to common factors. However, part of the abnormal returns generated in the first year after portfolio formation dissipates in the following two years. A similar pattern of returns around the earnings announcements of past winners and losers is also documented

Conditional heteroskedasticity in asset returns: a new approach

Abstract: This paper introduces an ARCH model (exponential ARCH) that (1) allows correlation between returns and volatility innovations (an important feature of stock market volatility changes), (2) eliminates the need for inequality constraints on parameters, and (3) allows for a straightforward interpretation of the "persistence" of shocks to volatility. In the above respects, it is an improvement over the widely-used GARCH model. The model is applied to study volatility changes and the risk premium on the CRSP Value-Weighted Market Index from 1962 to 1987. Copyright 1991 by The Econometric Society.