NEW YORK (TheStreet) -- With its shares up almost 70% year-to-date, e-commerce giant Amazon.com (AMZN) is crushing the broader indexes while punishing its doubters. But with such strong gains on the table (even factoring in the stock's 3% dip over the past month), investors are wondering, is now the time to cash in?

The concern? Amazon's -- seemingly -- expensive price-to-earnings ratio, which is actually in negative territory based on its full-year 2014 loss of 52 cents a share. Even when projecting out to fiscal 2015, where earnings estimates stand at around $1.58 a share, Amazon's forward P/E comes in at around 330 -- roughly 20 times the average forward P/E of companies in the S&P 500 (SPX) index.

But you would be wrong to think any of this matters to Amazon stock, which has shot up more than 1,000% over the past decade. Measured from their low of $10 a share after the dot-com bubble burst, Amazon shares are up more than 5,000% to around $520 today.

Amazon's P/E has actually averaged around 500 over the past five years -- an attention-grabbing number, given that the P/E of the S&P 500 has hovered between 18 and 22 during that period. But Amazon is nonetheless up some 260% over the same span. And given the moves CEO Jeff Bezos has started making, it remains foolish to think that P/E ratio issues will impede the stock's general upward trend.

It's more important to focus on how Amazon can further distance itself from big-box retailers like Wal-Mart (WMT) and Target (TGT) , while at the same time closing the gap on the likes of eBay (EBAY) in e-commerce and Netflix (NFLX) in the business of movie streaming.

Plus, when factoring Amazon's leadership position in cloud services, where its Amazon Web Services segment has a run rate of around $6 billion, the company has plenty of revenue streams to keep its stock momentum going. If Amazon's cloud service was its own entity, that business would be worth near $6 billion to $8 billion today. For some context, cloud giants Rackspace Hostings (RAX) and Box (BOX) have  market capitalizations of around $4.35 billion and $1.6 billion, respectively.

So, while Amazon's pricey P/E may continue to dominate bearish arguments, bulls have an equal number of reasons to expect the stock to keep climbing. And finally, as its ecosystem grows and its market share increases, Amazon's razor-blade model should transform into a profit behemoth, helping to slim down that high P/E ratio.

This article is commentary by an independent contributor. At the time of publication, the author held no positions in the stocks mentioned.

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