Margins Don’t Matter When Picking Stocks

With all the talk of high profit margins, it is worth remembering that they are nearly useless as a tool for individual stock selection. If you are an index investor, then margins (and maybe more accurately, ROEs) matter a great deal because when margins/ROEs revert to longer term norms, the market will likely suffer. But if you are instead building your own portfolio (whether it be through a quantitative screen or individual stock selection), then net profit margins haven’t mattered nearly as much as other measures like valuations across history.

In the below chart, you can see the historical excess return, by decile, for two factors: net margin (relative to companies in the same industry group) and valuation (relative to the entire market).  On the left hand side (decile 1) are companies with the cheapest valuations or highest margins, and on the right side (decile 10) are those with expensive valuations or very low margins.



You can see right away that where valuations have been highly predictive of strong future excess return, net margins haven’t been over the past 50 years. A high margin does not a great investment make–but a cheap price often does. 

Calculation Notes: deciles are run using a rolling annual rebalance. The universe is all stocks with an inflation adjusted market cap > $200MM between 1963-2014.  To control for differences in margins across industries, I’ve calculated margin relative to companies in the same industry group. I’ve also excluded companies with negative earnings.  Value is calculated using a variety of measures like price-to-sales, price-to-earnings, EBITDA/EV. The benchmark (against which I calculate the excess returns) is an equal weighted basket of all stocks with an inflation adjusted market cap > $200MM.