In order to justify the effort of selecting individual stocks, it's worth striving to beat the returns from a market index fund. But if you try your hand at stock picking, your risk returning less than the market. We regret to report that long term Nanosonics Limited (ASX:NAN) shareholders have had that experience, with the share price dropping 27% in three years, versus a market return of about 33%. The falls have accelerated recently, with the share price down 13% in the last three months.

Given the past week has been tough on shareholders, let's investigate the fundamentals and see what we can learn.

Check out our latest analysis for Nanosonics

While the efficient markets hypothesis continues to be taught by some, it has been proven that markets are over-reactive dynamic systems, and investors are not always rational. One flawed but reasonable way to assess how sentiment around a company has changed is to compare the earnings per share (EPS) with the share price.

During the three years that the share price fell, Nanosonics' earnings per share (EPS) dropped by 5.9% each year. The share price decline of 10% is actually steeper than the EPS slippage. So it seems the market was too confident about the business, in the past. Having said that, the market is still optimistic, given the P/E ratio of 139.13.

The image below shows how EPS has tracked over time (if you click on the image you can see greater detail).

Before buying or selling a stock, we always recommend a close examination of historic growth trends, available here.

A Different Perspective

Investors in Nanosonics had a tough year, with a total loss of 3.1%, against a market gain of about 4.2%. However, keep in mind that even the best stocks will sometimes underperform the market over a twelve month period. Longer term investors wouldn't be so upset, since they would have made 5%, each year, over five years. It could be that the recent sell-off is an opportunity, so it may be worth checking the fundamental data for signs of a long term growth trend. Before spending more time on Nanosonics it might be wise to click here to see if insiders have been buying or selling shares.

If you would prefer to check out another company -- one with potentially superior financials -- then do not miss this free list of companies that have proven they can grow earnings.

Please note, the market returns quoted in this article reflect the market weighted average returns of stocks that currently trade on Australian exchanges.

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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.