This article is written and contributed Greenbackd
Which price ratio best identifies undervalued stocks? It’s a fraught question, dependent on various factors including the time period tested, and the market capitalization and industries under consideration, but I believe a consensus is emerging.
The academic favorite remains book value-to-market capitalization (the inverse of price-to-book value). Fama and French maintain that it makes no difference which “price-to-a-fundamental” is employed, but if forced to choose favor book-to-market. In the Fama/French Forum on Dimensional Fund Advisor’s website they give it a tepid thumbs up despite the evidence that it’s not so great:
Data from Ken French’s website shows that sorting stocks on E/P or CF/P data produces a bigger spread than BtM over the last 55 years. Wouldn’t it make sense to use these other factors in addition to BtM to distinguish value from growth stocks? EFF/KRF: A stock’s price is just the present value of its expected future dividends, with the expected dividends discounted with the expected stock return (roughly speaking). A higher expected return implies a lower price.We always emphasize that different price ratios are just different ways to scale a stock’s price with a fundamental, to extract the information in the cross-section of stock prices about expected returns. One fundamental (book value, earnings, or cashflow) is pretty much as good as another for this job, and the average return spreads produced by different ratios are similar to and, in statistical terms, indistinguishable from one another. We like BtM because the book value in the numerator is more stable over time than earnings or cashflow, which is important for keeping turnover down in a value portfolio. Nevertheless, there are problems in all accounting variables and book value is no exception, so supplementing BtM with other ratios can in principal improve the information about expected returns. We periodically test this proposition, so far without much success.
There are a variety of papers on the utility of book value that I’ve beaten to death on Greenbackd. I used to think it was the duck’s knees because that was what all the early research seemed to say (See, for example, Roger Ibbotson’s “Decile Portfolios of the New York Stock Exchange, 1967 – 1984,” Werner F.M. DeBondt and Richard H. Thaler’s “Further Evidence on Investor Overreaction and Stock Market Seasonality”). Josef Lakonishok, Andrei Shleifer, and Robert Vishny’s Contrarian Investment, Extrapolation and Risk, which was updated by The Brandes Institute as Value vs Glamour: A Global Phenomenon reopened the debate, suggesting that price-to-earnings and price-to-cash flow might add something to price-to-book.
A number of more recent papers have moved away from book-to-market, and towards the enterprise multiple ((equity value + debt + preferred stock – cash)/ (EBITDA)). As far as I am aware, Tim Loughran and Jay W. Wellman got in first with their 2009 paper “The Enterprise Multiple Factor and the Value Premium,” which was a great unpublished paper, but became in 2010 a slightly less great published paper, “New Evidence on the Relation Between the Enterprise Multiple and Average Stock Returns,” suitable only for academics and masochists (but I repeat myself). The abstract to the 2009 paper (missing from the 2010 paper) cuts right to the chase:
Following the work of Fama and French (1992, 1993), there has been wide-spread usage of book-to-market as a factor to explain stock return patterns. In this paper, we highlight serious flaws with the use of book-to-market and offer a replacement factor for it. The Enterprise Multiple, calculated as (equity value + debt value + preferred stock – cash)/ EBITDA, is better than book-to-market in cross-sectional monthly regressions over 1963-2008. In the top three size quintiles (accounting for about 94% of total market value), EM is a highly significant measure of relative value, whereas book-to-market is insignificant.
The abstract says everything you need to know: Book-to-market is widely used (by academics), but it has serious flaws. The enterprise multiple is more predictive over a long period (1963 to 2008), and it’s much more predictive in big market capitalization stocks where book-to-market is essentially useless.
What serious flaws?
The big problem with book-to-market is that so much of the return is attributable to nano-cap stocks and “the January effect”:
Loughran (1997) examines the data used by Fama and French (1992) and finds that the results are driven by a January seasonal and the returns on microcap growth stocks. For the largest size quintile, accounting for about three-quarters of total market cap, Loughran finds that BE/ME has no significant explanatory power over 1963-1995. Furthermore, for the top three size quintiles, accounting for about 94% of total market cap, size and BE/ME are insignificant once January returns are removed. Fama and French (2006) confirm Loughran’s result over the post- 1963 period. Thus, for nearly the entire market value of largest stock market (the US) over the most important time period (post-1963), the value premium does not exist.
That last sentence bears repeating: For nearly the entire market value of largest stock market (the US) over the most important time period (post-1963),the value premium does not exist, which means that book-to-market is not predictive in stocks other than the smallest 6 percent by market cap. What about book-to-market in the stocks in that smallest 6 percent? It might not