AC Immune SA (NASDAQ:ACIU) shareholders would be excited to see that the share price has had a great month, posting a 34% gain and recovering from prior weakness. The annual gain comes to 113% following the latest surge, making investors sit up and take notice.

Following the firm bounce in price, AC Immune's price-to-sales (or "P/S") ratio of 24.1x might make it look like a strong sell right now compared to other companies in the Biotechs industry in the United States, where around half of the companies have P/S ratios below 11.7x and even P/S below 4x are quite common. Nonetheless, we'd need to dig a little deeper to determine if there is a rational basis for the highly elevated P/S.

How Has AC Immune Performed Recently?

Recent times have been advantageous for AC Immune as its revenues have been rising faster than most other companies. The P/S is probably high because investors think this strong revenue performance will continue. You'd really hope so, otherwise you're paying a pretty hefty price for no particular reason.

Do Revenue Forecasts Match The High P/S Ratio?

In order to justify its P/S ratio, AC Immune would need to produce outstanding growth that's well in excess of the industry.

Taking a look back first, we see that the company's revenues underwent some rampant growth over the last 12 months. Spectacularly, three year revenue growth has also set the world alight, thanks to the last 12 months of incredible growth. Therefore, it's fair to say the revenue growth recently has been superb for the company.

Shifting to the future, estimates from the four analysts covering the company suggest revenue should grow by 58% per year over the next three years. That's shaping up to be materially lower than the 205% per annum growth forecast for the broader industry.

In light of this, it's alarming that AC Immune's P/S sits above the majority of other companies. It seems most investors are hoping for a turnaround in the company's business prospects, but the analyst cohort is not so confident this will happen. There's a good chance these shareholders are setting themselves up for future disappointment if the P/S falls to levels more in line with the growth outlook.

The Key Takeaway

The strong share price surge has lead to AC Immune's P/S soaring as well. It's argued the price-to-sales ratio is an inferior measure of value within certain industries, but it can be a powerful business sentiment indicator.

Despite analysts forecasting some poorer-than-industry revenue growth figures for AC Immune, this doesn't appear to be impacting the P/S in the slightest. When we see a weak revenue outlook, we suspect the share price faces a much greater risk of declining, bringing back down the P/S figures. This places shareholders' investments at significant risk and potential investors in danger of paying an excessive premium.

And what about other risks? Every company has them, and we've spotted 2 warning signs for AC Immune (of which 1 is concerning!) you should know about.

Of course, profitable companies with a history of great earnings growth are generally safer bets. So you may wish to see this free collection of other companies that have reasonable P/E ratios and have grown earnings strongly.

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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.

Have feedback on this article? Concerned about the content? Get in touch with us directly. Alternatively, email editorial-team@simplywallst.com