If you want to compound wealth in the stock market, you can do so by buying an index fund. But in our experience, buying the right stocks can give your wealth a significant boost. For example, the Amgen Inc. (NASDAQ:AMGN) share price is up 84% in the last five years, slightly above the market return. It's also good to see a healthy gain of 35% in the last year.

Since the stock has added US$19b to its market cap in the past week alone, let's see if underlying performance has been driving long-term returns.

While markets are a powerful pricing mechanism, share prices reflect investor sentiment, not just underlying business performance. By comparing earnings per share (EPS) and share price changes over time, we can get a feel for how investor attitudes to a company have morphed over time.

During five years of share price growth, Amgen actually saw its EPS drop 11% per year.

Essentially, it doesn't seem likely that investors are focused on EPS. Since the change in EPS doesn't seem to correlate with the change in share price, it's worth taking a look at other metrics.

In contrast revenue growth of 3.7% per year is probably viewed as evidence that Amgen is growing, a real positive. It's quite possible that management are prioritizing revenue growth over EPS growth at the moment.

You can see how earnings and revenue have changed over time in the image below (click on the chart to see the exact values).

Amgen is well known by investors, and plenty of clever analysts have tried to predict the future profit levels. If you are thinking of buying or selling Amgen stock, you should check out this free report showing analyst consensus estimates for future profits.

What About Dividends?

As well as measuring the share price return, investors should also consider the total shareholder return (TSR). 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. So for companies that pay a generous dividend, the TSR is often a lot higher than the share price return. We note that for Amgen the TSR over the last 5 years was 113%, which is better than the share price return mentioned above. And there's no prize for guessing that the dividend payments largely explain the divergence!

A Different Perspective

We're pleased to report that Amgen shareholders have received a total shareholder return of 39% over one year. That's including the dividend. That gain is better than the annual TSR over five years, which is 16%. Therefore it seems like sentiment around the company has been positive lately. Given the share price momentum remains strong, it might be worth taking a closer look at the stock, lest you miss an opportunity. I find it very interesting to look at share price over the long term as a proxy for business performance. But to truly gain insight, we need to consider other information, too. For instance, we've identified 3 warning signs for Amgen (1 is concerning) that you should be aware of.

If you like to buy stocks alongside management, then you might just love this free list of companies. (Hint: insiders have been buying them).

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.