Amazon.com (AMZN -1.64%)  may have reached the tipping point of investor sentiment this quarter as expenses grew faster than revenue and the company guides to a loss in the coming quarter. Over the years, Amazon has been immune to valuation concerns because analysts believed the company could decide to turn a profit at any time by cutting back expenses.

Unfortunately that may no longer be the case as two critical financial metrics are becoming more of a concern for the market. Of course the real question is: What is to become of the stock over the next six months, one year, and beyond?

Profit guidance came in well below expectations
Amazon's revenue rose 22.8% from the prior year to $19.74 billion , nearly $300 million above the $19.42 billion consensus. But, earnings per share of $0.23 was a penny below estimates.

The company guided revenue in-line with consensus at $18.1 billion to $19.8 billion. Everything looks ok so far, but here's where things start to get scary. Operating income is now expected to be negative to the tune of $455 million to $550 million compared with expectations of a positive $189 million. Clearly, this is a major shift in profitability.

Media Growth Slows
Media is arguably the most important growth area for Amazon. The company has poured money into various Kindle devices over the years. It has become an amazingly cheap competitor to Netflix and started developing its own online video content -- but the growth appears to be slowing. In the quarter, the consolidated media segment grew at only 8.1 %. In the fourth quarter, consolidated media growth was 11%. While the difference between 11% and 8.1% may not seem like a lot, to the number crunchers, it represents a 26% drop, which can't be ignored.

Either of these two metrics could have been explained away, but the two of them together present a real problem. Combined these numbers indicate that Amazon's slowing growth could cause the company to invest its capital in new ventures that have no track record of profitability.

New businesses continue to soak up cash
Amazon has been busy this last quarter with the release of FireTv, , its attempts to fulfill its own deliveries rather than go through UPS , and its big expansion plans for its grocery service. The only problem is that every time one of these businesses is announced, it's another hit to profitability. If you add slowing growth to the mix, the company could be at a lull as expansion pressures profitability.

Now, before you start writing the barbed comments, realize that I am an Amazon Prime subscriber and I like the service. I'll also probably be a Fresh customer if it is offered in my area. The one thing you need to remember though is that a good company doesn't always make a good investment. In this case, there could be more downside coming.