For companies in stable industries, we have advocated employing Ben Graham's approach to determining a company's earnings power. While this approach of using a company's average earnings over a representative period is appropriate when the level of assets has not changed substantially, it may not be as useful at a time like this when companies are disposing of significant amounts of fixed assets.
Using the company's current earnings is also not an appropriate measure of a company's future earnings power. Current earnings are riddled with red ink due to current charges for labour reduction programs, asset impairments, and revenue drops that outpaced cost reductions.
While not perfect, a better method to estimating a company's future earnings power when assets have been impaired is by examining the company's record of return on assets. Provided the company is in an industry where technological advances are slow and where prices are stable, there will be, at the very least, a loose relationship between a company's earnings and its assets. By averaging a company's past return on assets over a representative period, and then applying this return to the company's current level of assets, the investor can get a better idea of the company's earnings power than if he estimated earnings power by simply extrapolating the company's current earnings, which are influenced by temporary effects.
The importance of limiting the application of this procedure to companies with price stability can not be stressed enough. For companies in commodity industries with volatile pricing, past returns are not neccessarily reflective of future earnings, and therefore the accuracy of this method reduces to the point where its usefulness is rather limited.
However, even if applied appropriately, it is important to note that this method of calculating a company's earnings power is by no means an exact science. Earnings will rarely be exactly proportional to a company's level of assets. However, for companies in slow-changing industries where price levels remain stable, an examination of the relationship between earnings and assets should assist the investor in making a more informed decision about the earnings power of a company under examination as a potential investment.
For a more advanced exercise, investors considering an investment in a capital intensive business may also try replacing return on assets with return on fixed assets.