Unfortunately for some shareholders, the Napco Security Technologies (NASDAQ:NSSC) share price has dived 32% in the last thirty days. Looking back further, the stock is up 6.4% in the last year.

All else being equal, a share price drop should make a stock more attractive to potential investors. In the long term, share prices tend to follow earnings per share, but in the short term prices bounce around in response to short term factors (which are not always obvious). 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). Investors have optimistic expectations of companies with higher P/E ratios, compared to companies with lower P/E ratios.

View our latest analysis for Napco Security Technologies

Does Napco Security Technologies Have A Relatively High Or Low P/E For Its Industry?

We can tell from its P/E ratio of 27.93 that there is some investor optimism about Napco Security Technologies. The image below shows that Napco Security Technologies has a higher P/E than the average (19.8) P/E for companies in the electronic industry.

That means that the market expects Napco Security Technologies will outperform other companies in its industry. The market is optimistic about the future, but that doesn't guarantee future growth. So further research is always essential. I often monitor director buying and selling.

How Growth Rates Impact P/E Ratios

Generally speaking the rate of earnings growth has a profound impact on a company's P/E multiple. When earnings grow, the 'E' increases, over time. And in that case, the P/E ratio itself will drop rather quickly. So while a stock may look expensive based on past earnings, it could be cheap based on future earnings.

It's nice to see that Napco Security Technologies grew EPS by a stonking 50% in the last year. And it has bolstered its earnings per share by 30% per year over the last five years. I'd therefore be a little surprised if its P/E ratio was not relatively high.

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. So it won't reflect the advantage of cash, or disadvantage of debt. 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).

Spending on growth might be good or bad a few years later, but the point is that the P/E ratio does not account for the option (or lack thereof).

So What Does Napco Security Technologies's Balance Sheet Tell Us?

Napco Security Technologies has net cash of US$12m. That should lead to a higher P/E than if it did have debt, because its strong balance sheets gives it more options.

The Bottom Line On Napco Security Technologies's P/E Ratio

Napco Security Technologies's P/E is 27.9 which is above average (18.3) in its market. The excess cash it carries is the gravy on top its fast EPS growth. To us, this is the sort of company that we would expect to carry an above average price tag (relative to earnings). What can be absolutely certain is that the market has become significantly less optimistic about Napco Security Technologies over the last month, with the P/E ratio falling from 41.2 back then to 27.9 today. For those who prefer to invest with the flow of momentum, that might be a bad sign, but for a contrarian, it may signal opportunity.

When the market is wrong about a stock, it gives savvy investors an opportunity. If the reality for a company is better than it expects, you can make money by buying and holding for the long term. So this free visualization of the analyst consensus on future earnings could help you make the right decision about whether to buy, sell, or hold.

You might be able to find a better buy than Napco Security Technologies. If you want a selection of possible winners, check out this free list of interesting companies that trade on a P/E below 20 (but have proven they can grow earnings).

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.