To the annoyance of some shareholders, American River Bankshares (NASDAQ:AMRB) shares are down a considerable 37% in the last month. The recent drop has obliterated the annual return, with the share price now down 29% over that longer period.

All else being equal, a share price drop should make a stock more attractive to potential investors. While the market sentiment towards a stock is very changeable, in the long run, the share price will tend to move in the same direction as earnings per share. So, on certain occasions, long term focussed investors try to take advantage of pessimistic expectations to buy shares at a better price. Perhaps the simplest way to get a read on investors' expectations of a business is to look at its Price to Earnings Ratio (PE Ratio). A high P/E implies that investors have high expectations of what a company can achieve compared to a company with a low P/E ratio.

Check out our latest analysis for American River Bankshares

Does American River Bankshares Have A Relatively High Or Low P/E For Its Industry?

We can tell from its P/E ratio of 9.79 that there is some investor optimism about American River Bankshares. The image below shows that American River Bankshares has a higher P/E than the average (8.9) P/E for companies in the banks industry.

That means that the market expects American River Bankshares will outperform other companies in its industry. Shareholders are clearly optimistic, but the future is always uncertain. So investors should always consider the P/E ratio alongside other factors, such as whether company directors have been buying shares.

How Growth Rates Impact P/E Ratios

When earnings fall, the 'E' decreases, over time. That means unless the share price falls, the P/E will increase in a few years. Then, a higher P/E might scare off shareholders, pushing the share price down.

It's great to see that American River Bankshares grew EPS by 13% in the last year. And its annual EPS growth rate over 5 years is 12%. So one might expect an above average P/E ratio.

Don't Forget: The P/E Does Not Account For Debt or Bank Deposits

The 'Price' in P/E reflects the market capitalization of the company. In other words, it does not consider any debt or cash that the company may have on the balance sheet. Theoretically, a business can improve its earnings (and produce a lower P/E in the future) by investing in growth. That means taking on debt (or spending its cash).

While growth expenditure doesn't always pay off, the point is that it is a good option to have; but one that the P/E ratio ignores.

How Does American River Bankshares's Debt Impact Its P/E Ratio?

American River Bankshares's net debt is 3.1% of its market cap. The market might award it a higher P/E ratio if it had net cash, but its unlikely this low level of net borrowing is having a big impact on the P/E multiple.

The Verdict On American River Bankshares's P/E Ratio

American River Bankshares has a P/E of 9.8. That's below the average in the US market, which is 13.0. The EPS growth last year was strong, and debt levels are quite reasonable. If it continues to grow, then the current low P/E may prove to be unjustified. What can be absolutely certain is that the market has become more pessimistic about American River Bankshares over the last month, with the P/E ratio falling from 15.6 back then to 9.8 today. For those who prefer to invest with the flow of momentum, that might be a bad sign, but for deep value investors this stock might justify some research.

Investors have an opportunity when market expectations about a stock are wrong. If it is underestimating a company, investors can make money by buying and holding the shares until the market corrects itself. So this free report on the analyst consensus forecasts could help you make a master move on this stock.

Of course, you might find a fantastic investment by looking at a few good candidates. So take a peek at this free list of companies with modest (or no) debt, trading on a P/E below 20.

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.