Many investors are still learning about the various metrics that can be useful when analysing a stock. This article is for those who would like to learn about Return On Equity (ROE). By way of learning-by-doing, we'll look at ROE to gain a better understanding of Austal Limited (ASX:ASB).

Over the last twelve months Austal has recorded a ROE of 9.7%. Another way to think of that is that for every A$1 worth of equity in the company, it was able to earn A$0.10.

See our latest analysis for Austal

How Do You Calculate Return On Equity?

The formula for return on equity is:

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

Or for Austal:

9.7% = AU$61m ÷ AU$631m (Based on the trailing twelve months to June 2019.)

It's easy to understand the 'net profit' part of that equation, but 'shareholders' equity' requires further explanation. It is all earnings retained by the company, plus any capital paid in by shareholders. You can calculate shareholders' equity by subtracting the company's total liabilities from its total assets.

What Does ROE Mean?

ROE looks at the amount a company earns relative to the money it has kept within the business. The 'return' is the amount earned after tax over the last twelve months. A higher profit will lead to a higher ROE. So, all else equal, investors should like a high ROE. That means ROE can be used to compare two businesses.

Does Austal Have A Good Return On Equity?

One simple way to determine if a company has a good return on equity is to compare it to the average for its industry. Importantly, this is far from a perfect measure, because companies differ significantly within the same industry classification. You can see in the graphic below that Austal has an ROE that is fairly close to the average for the Aerospace & Defense industry (9.7%).

That isn't amazing, but it is respectable. ROE doesn't tell us if the share price is low, but it can inform us to the nature of the business. For those looking for a bargain, other factors may be more important. For those who like to find winning investments this free list of growing companies with recent insider purchasing, could be just the ticket.

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 and second cases, the ROE will reflect this use of cash for investment in the business. In the latter case, the debt required for growth will boost returns, but will not impact the shareholders' equity. That will make the ROE look better than if no debt was used.

Combining Austal's Debt And Its 9.7% Return On Equity

Although Austal does use debt, its debt to equity ratio of 0.27 is still low. Its very respectable ROE, combined with only modest debt, suggests the business is in good shape. Careful use of debt to boost returns is often very good for shareholders. However, it could reduce the company's ability to take advantage of future opportunities.

But It's Just One Metric

Return on equity is one way we can compare the business quality of different companies. Companies that can achieve high returns on equity without too much debt are generally of good quality. If two companies have around the same level of debt to equity, and one has a higher ROE, I'd generally prefer the one with higher ROE.

But when a business is high quality, the market often bids it up to a price that reflects this. It is important to consider other factors, such as future profit growth -- and how much investment is required going forward. So you might want to check this FREE visualization of analyst forecasts for the company.

If you would prefer check out another company -- one with potentially superior financials -- then do not miss thisfree list of interesting companies, that have HIGH return on equity 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.