Potbelly Corporation's (NASDAQ:PBPB ) stock didn't jump after it announced some healthy earnings. We did some digging and believe investors may be worried about some underlying factors in the report.

See our latest analysis for Potbelly

A Closer Look At Potbelly's Earnings

In high finance, the key ratio used to measure how well a company converts reported profits into free cash flow (FCF) is the accrual ratio (from cashflow). In plain english, this ratio subtracts FCF from net profit, and divides that number by the company's average operating assets over that period. The ratio shows us how much a company's profit exceeds its FCF.

As a result, a negative accrual ratio is a positive for the company, and a positive accrual ratio is a negative. While it's not a problem to have a positive accrual ratio, indicating a certain level of non-cash profits, a high accrual ratio is arguably a bad thing, because it indicates paper profits are not matched by cash flow. To quote a 2014 paper by Lewellen and Resutek, "firms with higher accruals tend to be less profitable in the future".

Over the twelve months to December 2024, Potbelly recorded an accrual ratio of 1.56. Ergo, its free cash flow is significantly weaker than its profit. As a general rule, that bodes poorly for future profitability. To wit, it produced free cash flow of US$379k during the period, falling well short of its reported profit of US$40.3m. Potbelly's free cash flow actually declined over the last year, but it may bounce back next year, since free cash flow is often more volatile than accounting profits. However, we can see that a recent tax benefit, along with unusual items, have impacted its statutory profit, and therefore its accrual ratio.

That might leave you wondering what analysts are forecasting in terms of future profitability. Luckily, you can click here to see an interactive graph depicting future profitability, based on their estimates.

The Impact Of Unusual Items On Profit

Potbelly's profit suffered from unusual items, which reduced profit by US$3.6m in the last twelve months. If this was a non-cash charge, it would have made the accrual ratio better, if cashflow had stayed strong, so it's not great to see in combination with an uninspiring accrual ratio. It's never great to see unusual items costing the company profits, but on the upside, things might improve sooner rather than later. We looked at thousands of listed companies and found that unusual items are very often one-off in nature. And, after all, that's exactly what the accounting terminology implies. If Potbelly doesn't see those unusual expenses repeat, then all else being equal we'd expect its profit to increase over the coming year.

An Unusual Tax Situation

Moving on from the accrual ratio, we note that Potbelly profited from a tax benefit which contributed US$34m to profit. This is meaningful because companies usually pay tax rather than receive tax benefits. The receipt of a tax benefit is obviously a good thing, on its own. However, our data indicates that tax benefits can temporarily boost statutory profit in the year it is booked, but subsequently profit may fall back. Assuming the tax benefit is not repeated every year, we could see its profitability drop noticeably, all else being equal. While we think it's good that the company has booked a tax benefit, it does mean that there's every chance the statutory profit will come in a lot higher than it would be if the income was adjusted for one-off factors.

Our Take On Potbelly's Profit Performance

Summing up, Potbelly's unusual items suggest that its statutory earnings were temporarily depressed, while its tax benefit is having the opposite effect, and its accrual ratio indicates a lack of free cash flow relative to profit. Considering all this we'd argue Potbelly's profits probably give an overly generous impression of its sustainable level of profitability. With this in mind, we wouldn't consider investing in a stock unless we had a thorough understanding of the risks. You'd be interested to know, that we found 2 warning signs for Potbelly and you'll want to know about them.

Our examination of Potbelly has focussed on certain factors that can make its earnings look better than they are. And, on that basis, we are somewhat skeptical. But there are plenty of other ways to inform your opinion of a company. Some people consider a high return on equity to be a good sign of a quality business. So you may wish to see this free collection of companies boasting high return on equity, or this list of stocks with high insider ownership.

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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.