Do the Merits Matter More? The Impact of the Private Securities Litigation Reform Act

This article examines the effect of the Private Securities LitigationReform Act of 1995 (PSLRA) on stockholder lawsuits. We explorethe role of restatements, earnings forecasts, and insider tradingin the filing and resolution of lawsuits for a sample of hightechnology firms. Consistent with our predictions, there isa post-PSLRA shift away from litigation based on forward-lookingearnings disclosures. Conversely, there is a significantly greatercorrelation between litigation and both earnings restatementsand abnormal insider selling after the PSLRA. Finally, we finda post-PSLRA increase in the likelihood of settlement for casesinvolving earnings restatements.     

When are contrarian profits due to stock market overreaction?

If returns on some stocks systematically lead or lag those ofothers, a portfolio strategy that sells 'winners' and buys 'losers'can produce positive expected returns, even if no stock's returnsare negatively autocorrelated as virtually all models of overreactionimply. Using a particular contrarian strategy we show that,despite negative autocorrelation in individual stock returns,weekly portfolio returns are strongly positively autocorrelatedand are the result of important cross-auto-correlations. Wefind that the returns of large stocks lead those of smallerstocks, and we present evidence against overreaction as theonly source of contrarian profits.     

Stock market prices do not follow random walks: evidence from a simple specification test

In this article we test the random walk hypothesis for weeklystock market returns by comparing variance estimators derivedfrom data sampled at different frequencies. The random walkmodel is strongly rejected for the entire sample period (1962-1985)and for all subperiods for a variety of aggregate returns indexesand size-sorted portfolios. Although the rejections are duelargely to the behavior of small stocks, they cannot be attributedcompletely to the effects of infrequent trading or time-varyingvolatilities. Moreover, the rejection of the random walk forweekly returns does not support a mean-reverting model of assetprices.     

Consumer-centered vs. job-centered health insurance

Most employees and their dependents in the United States have health insurance provided by the employer or labor-management health and welfare fund. In this system, employees and their families lose their health insurance when the breadwinner loses his or her job while, at the same time, a Medicaid beneficiary can lose Medicaid eligibility by getting a job, even a poorly paid one. Most health insurance pays the doctor on the basis of fee-for-service and the hospital on the basis of cost-reimbursement, rewarding both with more revenue for providing more and more costly services. The insured employee has little or no incentive to seek out a less costly provider. There are no rewards for economy in this system. It should be little wonder, then, that health care costs are out of control. There are alternative financing and delivery systems with built-in incentives to use resources economically, but, the author of this article asserts, their ability to compete and attract patients with their superior economic efficiency is blocked by many laws and government programs. The author believes that the most effective and acceptable way to get costs under control, and at the same time achieve universal coverage, would be through a system of fair economic competition. He discusses his Consumer Choice Health Plan proposal and describes how one of the main barriers to competition is today's system of job-linked health insurance.     

Index-futures arbitrage and the behavior of stock index futures prices

This article examines intraday transaction data for S&P500 stock index futures prices and the intraday quotes for theunderlying index. The data indicate that the futures price changesare uncorrelated and that the variability of these price changesexceeds the variability of price changes in the S&P 500index. This excess variability of the futures over the indexremains even after controlling for the nonsynchronous pricesin the index quotes, which induces auto-correlation in the indexchanges. We advance and examine empirically two hypotheses regardingthe difference between the futures price and its theoreticalvalue: that this 'mispricing' increases on average with maturity,and that it is path-dependent. Evidence supporting these hypothesesis presented.     

Data-snooping biases in tests of financial asset pricing models

Tests of financial asset pricing models may yield misleadinginferences when properties of the data are used to constructthe test statistics. In particular, such tests are often basedon returns to portfolios of common stock, where portfolios areconstructed by sorting on some empirically motivated characteristicof the securities such as market value of equity. Analyticalcalculations, Monte Carlo simulations, and two empirical examplesshow that the effects of this type of data snooping can be substantial.