The Journal of Finance

Does the Stock Market Rationally Reflect Fundamental Values?

Published: 07/01/1986   |   DOI: 10.1111/j.1540-6261.1986.tb04519.x

LAWRENCE H. SUMMERS

This paper examines the power of statistical tests commonly used to evaluate the efficiency of speculative markets. It shows that these tests have very low power. Market valuations can differ substantially and persistently from the rational expectation of the present value of cash flows without leaving statistically discernible traces in the pattern of ex‐post returns. This observation implies that speculation is unlikely to ensure rational valuations, since similar problems of identification plague both financial economists and would be speculators.

On Economics and Finance

Published: 07/01/1985   |   DOI: 10.1111/j.1540-6261.1985.tb04985.x

LAWRENCE H. SUMMERS

New Evidence That Taxes Affect the Valuation of Dividends

Published: 12/01/1984   |   DOI: 10.1111/j.1540-6261.1984.tb04914.x

JAMES M. POTERBA, LAWRENCE H. SUMMERS

This paper uses British data to examine the effects of dividend taxes on investors' relative valuation of dividends and capital gains. British data offer great potential to illuminate the dividends and taxes question, since there have been two radical changes and several minor reforms in British dividend tax policy during the last 30 years. Studying the relationship between dividends and stock price movements during different tax regimes offers an ideal controlled experiment for assessing the effects of taxes on investors' valuation of dividends. Using daily data on a small sample of firms, and monthly data on a much broader sample, we find clear evidence that taxes affect the equilibrium relationship between dividend yields and market returns. These findings suggest that taxes are important determinants of security market equilibrium and deepen the puzzle of why firms pay dividends.

The Size and Incidence of the Losses from Noise Trading

Published: 07/01/1989   |   DOI: 10.1111/j.1540-6261.1989.tb04385.x

J. BRADFORD DE LONG, ANDREI SHLEIFER, LAWRENCE H. SUMMERS, ROBERT J. WALDMANN

Recent empirical research has identified a significant amount of volatility in stock prices that cannot easily be explained by changes in fundamentals; one interpretation is that asset prices respond not only to news but also to irrational “noise trading.” We assess the welfare effects and incidence of such noice trading using an overlapping‐generations model that gives investors short horizons. We find that the additional risk generated by noise trading can reduce the capital stock and consumption of the economy, and we show that part of that cost may be borne by rational investors. We conclude that the welfare costs of noise trading may be large if the magnitude of noise in aggregate stock prices is as large as suggested by some of the recent empirical litrature on the excess volatility of the market.

Positive Feedback Investment Strategies and Destabilizing Rational Speculation

Published: 06/01/1990   |   DOI: 10.1111/j.1540-6261.1990.tb03695.x

J. BRADFORD DE LONG, ANDREI SHLEIFER, LAWRENCE H. SUMMERS, ROBERT J. WALDMANN

Analyses of rational speculation usually presume that it dampens fluctuations caused by “noise” traders. This is not necessarily the case if noise traders follow positive‐feedback 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 forward‐looking 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.