Tuesday, June 16, 2009

A Good Paper on "Return Factors"

Robert Haugen is one of (if not THE) best-known figure in the behavioral finance (i.e. "markets are not efficient") camp. He wrote one of the earliest books on the topic in 1995 (The New Finance) and runs a quantitative finance shop based on much of his research. In a recent paper with Nardin Baker of UC-Irvine, he examines the explanatory and predictive ability of a wide array of observable factors. Here's the 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.
Here are some of the factors that they find statistically significant:
  • Price Multiples such as price to cash flow, sales, book value, and earnings (negative relationship with subsequent returns
  • Profitabiliy measures such as ROE, ROA, and Profit Margins (positive relationship)
  • Volatility in returns, whether "raw" or "residual" (negative relationship)
  • Momentum (positive relationship)
  • Recent returns (positive rel;ationship with last year's return, negative with last month's return, and last month's "residual" return)
Read the whole thing here

It's worth reading. Haugen is clearly not an ubiased observer (he does run a shop based on the idea that markets are inefficient), and there's definitely some serious data mining going on here. Having said that, it's definitely worth reading. It gives a very good summary of many of the factors that prior research has found to be significantly related to subsequent returns. I'll be making the next group of student in Unknown University's student-managed fund read it.

HT: Empirical Finance Research