Archrock (NYSE:AROC) shareholders are no doubt pleased to see that the share price has bounced 36% in the last month alone, although it is still down 40% over the last quarter. But shareholders may not all be feeling jubilant, since the share price is still down 48% in the last year.

Assuming no other changes, a sharply higher share price makes a stock less attractive to potential buyers. 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 some would prefer to hold off buying when there is a lot of optimism towards a stock. One way to gauge market expectations of a stock 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 Archrock

How Does Archrock's P/E Ratio Compare To Its Peers?

We can tell from its P/E ratio of 46.91 that there is some investor optimism about Archrock. As you can see below, Archrock has a much higher P/E than the average company (10.2) in the energy services industry.

Its relatively high P/E ratio indicates that Archrock shareholders think it will perform better than other companies in its industry classification. Shareholders are clearly optimistic, but the future is always uncertain. So investors should delve deeper. I like to check if company insiders have been buying or selling .

How Growth Rates Impact P/E Ratios

Probably the most important factor in determining what P/E a company trades on is the earnings growth. Earnings growth means that in the future the 'E' will be higher. Therefore, even if you pay a high multiple of earnings now, that multiple will become lower in the future. And as that P/E ratio drops, the company will look cheap, unless its share price increases.

Archrock's earnings per share fell by 70% in the last twelve months.

A Limitation: P/E Ratios Ignore Debt and Cash In The Bank

One drawback of using a P/E ratio is that it considers market capitalization, but not the balance sheet. In other words, it does not consider any debt or cash that the company may have on the balance sheet. The exact same company would hypothetically deserve a higher P/E ratio if it had a strong balance sheet, than if it had a weak one with lots of debt, because a cashed up company can spend on growth.

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 Archrock's Balance Sheet Tell Us?

Net debt totals a substantial 236% of Archrock's market cap. This level of debt justifies a relatively low P/E, so remain cognizant of the debt, if you're comparing it to other stocks.

The Bottom Line On Archrock's P/E Ratio

Archrock's P/E is 46.9 which is way above average (14.3) in its market. With significant debt and no EPS growth last year, shareholders are betting on an improvement in earnings from the company. What we know for sure is that investors have become much more excited about Archrock recently, since they have pushed its P/E ratio from 34.5 to 46.9 over the last month. For those who prefer to invest with the flow of momentum, that might mean it's time to put the stock on a watchlist, or research it. But the contrarian may see it as a missed opportunity.

Investors have an opportunity when market expectations about a stock are wrong. 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 earningscould help you make the right decision about whether to buy, sell, or hold.

You might be able to find a better buy than Archrock. 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 ateditorial-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.