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. By way of learning-by-doing, we'll look at ROE to gain a better understanding of Marathon Petroleum Corporation (NYSE:MPC).

Return on Equity or ROE is a test of how effectively a company is growing its value and managing investors' money. In short, ROE shows the profit each dollar generates with respect to its shareholder investments.

How To Calculate Return On Equity?

The formula for return on equity is:

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

So, based on the above formula, the ROE for Marathon Petroleum is:

31% = US$8.8b ÷ US$28b (Based on the trailing twelve months to June 2024).

The 'return' is the income the business earned over the last year. One way to conceptualize this is that for each $1 of shareholders' capital it has, the company made $0.31 in profit.

Does Marathon Petroleum Have A Good ROE?

One simple way to determine if a company has a good return on equity is to compare it to the average for its industry. However, this method is only useful as a rough check, because companies do differ quite a bit within the same industry classification. Pleasingly, Marathon Petroleum has a superior ROE than the average (16%) in the Oil and Gas industry.

That's what we like to see. Bear in mind, a high ROE doesn't always mean superior financial performance. A higher proportion of debt in a company's capital structure may also result in a high ROE, where the high debt levels could be a huge risk . Our risks dashboardshould have the 3 risks we have identified for Marathon Petroleum.

How Does Debt Impact Return On Equity?

Most companies need money -- from somewhere -- 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 used for growth will improve returns, but won't affect the total equity. Thus the use of debt can improve ROE, albeit along with extra risk in the case of stormy weather, metaphorically speaking.

Marathon Petroleum's Debt And Its 31% ROE

Marathon Petroleum does use a high amount of debt to increase returns. It has a debt to equity ratio of 1.01. There's no doubt the ROE is impressive, but it's worth keeping in mind that the metric could have been lower if the company were to reduce its debt. Investors should think carefully about how a company might perform if it was unable to borrow so easily, because credit markets do change over time.

Summary

Return on equity is one way we can compare its business quality of different companies. In our books, 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 ROE is just one piece of a bigger puzzle, since high quality businesses often trade on high multiples of earnings. 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 take a peek at this data-rich interactive graph of forecasts for the company.

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

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This article by Simply Wall St is general in nature. We provide commentary based on historical data and analyst forecasts only using an unbiased methodology and our articles are not intended to be financial advice. It does not constitute a recommendation to buy or sell any stock, and does not take account of your objectives, or your financial situation. We aim to bring you long-term focused analysis driven by fundamental data. Note that our analysis may not factor in the latest price-sensitive company announcements or qualitative material. Simply Wall St has no position in any stocks mentioned.