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Abstract:
This article provides conclusive evidence that the U.S. stock market is highly inefficient. Our results, spanning a 45 year period, indicate dramatic, consistent, and negative payoffs to measures of risk, positive payoffs to measures of current profitability, positive payoffs to measures of cheapness, positive payoffs to momentum in stock return, and negative payoffs to recent stock performance. Our comprehensive expected return factor model successfully predicts future return, out of sample, in each of the forty-five years covered by our study save one. Stunningly, the ten percent of stocks with highest expected return, in aggregate, are low risk and highly profitable, with positive trends in profitability. They are cheap relative to current earnings, cash flow, sales, and dividends. They have relatively large market capitalization and positive price momentum over the previous year. The ten percent with lowest expected return (decile 1) have exactly the opposite profile, and we find a smooth transition in the profiles as we go from 1 through 10. We split the whole 45-year time period into five sub-periods, and find that the relative profiles hold over all periods. Undeniably, the highest expected return stocks are, collectively, highly attractive; the lowest expected return stocks are very scary - results fatal to the efficient market hypothesis. While this evidence is consistent with risk loving in the cross-section, we also present strong evidence consistent with risk aversion in the market aggregate's longitudinal behavior. These behaviors cannot simultaneously exist in an efficient market.

efficient market, factor model, markowitz, optimization, inefficient market, risk

Abstract:
This paper tests a theoretical model of the basis and open interest of stock index futures. The model is based on the differences between stock and futures in terms of investors' ability to customize stock portfolios and liquidity. Empirical evidence confirms the model's prediction that increased volatility decreases the basis and increases open interest.

Abstract:
Evidence is presented that the determinants of the cross-section of expected stock returns are stable in their identity and influence from period to period and from country to country. The determinants are related to risk, liquidity, price-level, growth potential, and stock price history. Out-of-sample predictions of expected return, using trailing moving average values for the payoffs to these firm characteristics, are strongly and consistently accurate. Moreover, the stocks with higher expected and realized return rates of return are generally and unambiguously of lower risk than stocks with lower returns. Given the nature of the tests, it is highly unlikely that these results may be attributed to bias or data snooping. Consequently, the results seem to reveal a major failure in the Efficient Markets Hypothesis.

Abstract:
A re-entry theory for abnormal behavior of financial markets in January is derived and tested. The model predicts that, by optimally shifting portfolios to mimic a benchmark, successful investment managers lock in superior performance, while unsuccessful investment managers lock out possible termination. Price pressure, ensuing from re-entry, occurs at the turn of the year, when managers uniformly prefer to reverse benchmark matching strategies. Analysis of professionally managed portfolios over the period 1969-1989 provides mixed support for the theory. At year-end, extreme performers exhibit some movement toward the S&P 500 index. This pattern reverses shortly after the turn of the year.