If you want to compound wealth in the stock market, you can do so by buying an index fund. But you can do a lot better than that by buying good quality businesses for attractive prices. For example, the Power Integrations, Inc. (NASDAQ:POWI) share price is 81% higher than it was five years ago, which is more than the market average. Zooming in, the stock is actually down 13% in the last year.

So let's assess the underlying fundamentals over the last 5 years and see if they've moved in lock-step with shareholder returns.

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 imperfect but simple way to consider how the market perception of a company has shifted is to compare the change in the earnings per share (EPS) with the share price movement.

During five years of share price growth, Power Integrations actually saw its EPS drop 3.8% per year.

So it's hard to argue that the earnings per share are the best metric to judge the company, as it may not be optimized for profits at this point. Therefore, it's worth taking a look at other metrics to try to understand the share price movements.

The modest 1.2% dividend yield is unlikely to be propping up the share price. On the other hand, Power Integrations' revenue is growing nicely, at a compound rate of 8.0% over the last five years. It's quite possible that management are prioritizing revenue growth over EPS growth at the moment.

The company's revenue and earnings (over time) are depicted in the image below (click to see the exact numbers).

Balance sheet strength is crucial. It might be well worthwhile taking a look at our free report on how its financial position has changed over time.

What About Dividends?

When looking at investment returns, it is important to consider the difference between total shareholder return (TSR) and share price return. Whereas the share price return only reflects the change in the share price, the TSR includes the value of dividends (assuming they were reinvested) and the benefit of any discounted capital raising or spin-off. It's fair to say that the TSR gives a more complete picture for stocks that pay a dividend. As it happens, Power Integrations' TSR for the last 5 years was 88%, which exceeds the share price return mentioned earlier. And there's no prize for guessing that the dividend payments largely explain the divergence!

A Different Perspective

Investors in Power Integrations had a tough year, with a total loss of 13% (including dividends), against a market gain of about 26%. Even the share prices of good stocks drop sometimes, but we want to see improvements in the fundamental metrics of a business, before getting too interested. Longer term investors wouldn't be so upset, since they would have made 13%, 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. While it is well worth considering the different impacts that market conditions can have on the share price, there are other factors that are even more important. Even so, be aware that Power Integrations is showing 2 warning signs in our investment analysis , you should know about...

But note: Power Integrations may not be the best stock to buy. So take a peek at this free list of interesting companies with past earnings growth (and further growth forecast).

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