One of the best investments we can make is in our own knowledge and skill set. With that in mind, this article will work through how we can use Return On Equity (ROE) to better understand a business. To keep the lesson grounded in practicality, we'll use ROE to better understand bioMérieux S.A. (EPA:BIM).

bioMérieux has a ROE of 12%, based on the last twelve months. That means that for every €1 worth of shareholders' equity, it generated €0.12 in profit.

Check out our latest analysis for bioMérieux

How Do I Calculate Return On Equity?

The formula for ROE is:

Return on Equity = Net Profit (from continuing operations) ÷ Shareholders' Equity

Or for bioMérieux:

12% = €270m ÷ €2.3b (Based on the trailing twelve months to December 2019.)

Most readers would understand what net profit is, but it’s worth explaining the concept of shareholders’ equity. It is the capital paid in by shareholders, plus any retained earnings. Shareholders' equity can be calculated by subtracting the total liabilities of the company from the total assets of the company.

What Does ROE Mean?

Return on Equity measures a company's profitability against the profit it has kept for the business (plus any capital injections). The 'return' is the amount earned after tax over the last twelve months. A higher profit will lead to a higher ROE. So, as a general rule, a high ROE is a good thing. That means ROE can be used to compare two businesses.

Does bioMérieux Have A Good ROE?

By comparing a company's ROE with its industry average, we can get a quick measure of how good it is. Importantly, this is far from a perfect measure, because companies differ significantly within the same industry classification. The image below shows that bioMérieux has an ROE that is roughly in line with the Medical Equipment industry average (11%).

That's not overly surprising. ROE can give us a view about company quality, but many investors also look to other factors, such as whether there are insiders buying shares. If you like to buy stocks alongside management, then you might just love this free list of companies. (Hint: insiders have been buying them).

Why You Should Consider Debt When Looking At ROE

Companies usually need to invest money to grow their profits. The cash for investment can come from prior year profits (retained earnings), issuing new shares, or borrowing. In the first two cases, the ROE will capture this use of capital to grow. In the latter case, the debt required for growth will boost returns, but will not impact the shareholders' equity. In this manner the use of debt will boost ROE, even though the core economics of the business stay the same.

bioMérieux's Debt And Its 12% ROE

Although bioMérieux does use debt, its debt to equity ratio of 0.20 is still low. The fact that it achieved a fairly good ROE with only modest debt suggests the business might be worth putting on your watchlist. Conservative use of debt to boost returns is usually a good move for shareholders, though it does leave the company more exposed to interest rate rises.

The Bottom Line On ROE

Return on equity is one way we can compare the business quality of different companies. In my book the highest quality companies have high return on equity, despite low debt. If two companies have the same ROE, then I would generally prefer the one with less debt.

But when a business is high quality, the market often bids it up to a price that reflects this. Profit growth rates, versus the expectations reflected in the price of the stock, are a particularly important to consider. So you might want to take a peek at this data-rich interactive graph of forecasts for the company.

But note: bioMérieux may not be the best stock to buy. So take a peek at this free list of interesting companies with high ROE and low debt.

If you spot an error that warrants correction, please contact the editor at editorial-team@simplywallst.com. This article by Simply Wall St is general in nature. It does not constitute a recommendation to buy or sell any stock, and does not take account of your objectives, or your financial situation. Simply Wall St has no position in the stocks mentioned.

We aim to bring you long-term focused research analysis driven by fundamental data. Note that our analysis may not factor in the latest price-sensitive company announcements or qualitative material. Thank you for reading.