Every investor on earth makes bad calls sometimes. But you want to avoid the really big losses like the plague. So consider, for a moment, the misfortune of S4 Capital plc (LON:SFOR) investors who have held the stock for three years as it declined a whopping 90%. That would be a disturbing experience. And more recent buyers are having a tough time too, with a drop of 46% in the last year. We really hope anyone holding through that price crash has a diversified portfolio. Even when you lose money, you don't have to lose the lesson.

Since shareholders are down over the longer term, lets look at the underlying fundamentals over the that time and see if they've been consistent with returns.

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S4 Capital isn't currently profitable, so most analysts would look to revenue growth to get an idea of how fast the underlying business is growing. When a company doesn't make profits, we'd generally hope to see good revenue growth. That's because it's hard to be confident a company will be sustainable if revenue growth is negligible, and it never makes a profit.

In the last three years, S4 Capital saw its revenue grow by 3.8% per year, compound. That's not a very high growth rate considering it doesn't make profits. But the share price crash at 24% per year does seem a bit harsh! We generally don't try to 'catch the falling knife'. Before considering a purchase, take a look at the losses the company is racking up.

The image below shows how earnings and revenue have tracked over time (if you click on the image you can see greater detail).

You can see how its balance sheet has strengthened (or weakened) over time in this free interactive graphic.

Investors in S4 Capital had a tough year, with a total loss of 46% (including dividends), against a market gain of about 7.5%. 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. Unfortunately, last year's performance may indicate unresolved challenges, given that it was worse than the annualised loss of 14% over the last half decade. Generally speaking long term share price weakness can be a bad sign, though contrarian investors might want to research the stock in hope of a turnaround. It's always interesting to track share price performance over the longer term. But to understand S4 Capital better, we need to consider many other factors. Take risks, for example - S4 Capital has 2 warning signs we think you should be aware of.