Death and taxes. Those are the surefire things in life. Oh and's (NASDAQ:AMZN) minuscule profits, too. Quarter in and quarter out, it seems like it's the same old story: Jeff Bezos and company make billions in revenue with nothing to show for it. At least that's how many view it. And to an extent, I get it. I mean, P/E ratios tell the whole story, right? Wrong.

Where the money isn't
One of the general themes of recent earnings seasons has been top-line organic revenue growth (or the lack thereof). Many companies have done a great job of controlling costs in order to keep earnings growth alive, but revenue growth has been less than stellar, thanks to a sluggish global economy. Just look at McDonald's (NYSE:MCD). Sales since 2011 have been utterly flat, and while earnings per share have grown about 3.5%, cost-cutting can only get you so far.

Amazon, on the other hand, is growing the top line like they have a bet to win. Sales are up almost 38% since 2011 and, if we look back a full five years, sales have grown at a whopping 29.5% compound annual growth rate. That's not too shabby for a sluggish economy coming out of recession. Of course, that's not the number that most people focus on when it comes to Amazon. It's net income that has everybody's knickers in a knot. How can a company that makes so much revenue be so unprofitable? And why in the world are we paying 800 times earnings for it?

You say yes, I say no
Investing, at its core, is disagreeing isn't it? For every buyer there's a seller, and both parties happen to think they're right. With that said, I'll submit that I don't believe valuing Amazon based on net income is the best way to look at it. I know, I know... plenty of Amazon bears out there want to throw a pie at my face when I say this. But it's just for perspective, so follow me for a second. 

Amazon's business model operates with what's known as a negative cash conversion cycle. What this means in English is that Amazon gets paid for what it sells to customers like you and me well before they ever have to actually pay for it itself. This is important because the net income number doesn't reflect the advantages of a negative cash conversion cycle; but the cash flow from operations (CFFO) number on the cash flow statement does. It adds back those accounts payable as if it's cash that hasn't flowed out of the business, yet it's cash that Amazon can use to reinvest to grow the business.

It's all about the cash flow
So it becomes a bit more clear why in their earnings calls, Amazon management reiterates time and time again that they are not focused on earnings, they are focused on cash flow; both operating and free. CFO Tom Szkutak:

From a margin standpoint, always challenging to predict where that will come out in terms of absolute numbers, but what we will do is we want to make sure that we try to maximize free cash flow. That's something that we've always said... So again, our goal is to -- we don't focus on individual margins. Our goal is to make sure that we generate free cash flow, large amounts of free cash flow, and use that capital efficiently. And so those are goals that we have. And we certainly think that opportunity is there in each of the businesses that we operate in.

The simple definition of free cash flow is CFFO less capital expenditures (capex). So free cash flow is very dependent on how much management spends in capex, and management has certainly boosted capex over the last five years. In 2008, capex was about 20% of CFFO. Over the last 12 months, it was 94%. Translation: Amazon is investing big time for the future. And just so we're clear, it's not like Amazon is financially strapped, either, with almost $7.5 billion in cash and equivalents on the balance sheet.

Investing in the bottom line
We all make our own investment decisions, and some make more sense than others. And I understand why some can't get comfortable with owning Amazon stock. But I do believe it's wise to look further than just the anemic earnings per share the company puts up every quarter. Bezos is clearly building something much, much bigger than a quarterly number for Wall Street to chew on. That's why I own shares; I truly believe Jeff Bezos is one of the greatest long-term investors of our time.

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Jason Moser owns shares of The Motley Fool recommends and McDonald's. The Motley Fool owns shares of and McDonald's. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.