The white-hot speculation in Apple (AAPL) shares continues to intensify. The price topped $600 a share briefly two weeks ago, ahead of the release of the new iPad, and regained that territory on the March 19 news the company would pay a dividend and buy back shares.

Quite frankly, since I have not been too interested in individual short positions (or non-money-printing-r​elated long ideas), I haven't spent much time focusing on Apple. However, a recent question from a subscriber to FleckensteinCapital.​com about what I thought the company might be worth caused me to examine it more closely.

Has Apple bitten off more than it can chew?

I am sort of embarrassed to admit how shocked I was to realize that Apple has gained almost 50% this year, and, of course -- given its heavy weighting -- that is a big reason the Nasdaq ($COMPX) has done as well as it has. And since the Nasdaq has been strong, Apple's momentum has probably spilled over to help boost the price of other shares as well.

• Opposite view: Why Apple will hit $1,650

To put those incomprehensibly gigantic numbers into perspective, the increase in the price of Apple shares alone is equal to two-thirds of the value of Microsoft (MSFT). (Microsoft publishes MSN Money.)

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I know Apple aficionados hate to hear this, but there is really no comparison between Apple and Microsoft in terms of sustainability of the enterprise. Apple is a consumer products company, and a damn good one. But consumers are notoriously fickle. There is no guarantee that people will want to continue to replace (or "refresh," if you prefer silly modern jargon) their hardware as often in the future as they have in the past, or even choose Apple products, for that matter.

Nevertheless, at the moment, the market has to some extent become "all Apple, all the time," with this week's action being driven by that announcement of a fairly aggressive dividend policy. It will be interesting to see how smart that decision looks in a couple of years.

Ripe for the picking?

As successful as Apple has been, probably some time in the next couple of quarters, if not sooner, I think it is much more likely to make a great short sell (for those who feel lucky, brave, or both) than a great investment from the long side. Given the money-printing environment we have been in, I may or may not try that tactic (it all depends on the setup).

Owners of Apple stock would be well advised to carefully evaluate the risk/reward picture. The risks may be higher than you think.

I think it is important to recognize just how momentum-oriented and speculative the stock has become, for the very reason that it exerts an outsized influence on the tape.

As a result, if Apple does roll over, it could precipitate a correction in the market that other fundamental bad news has been unable to produce. We will just have to see how it plays out, but I, for one, can't help but pay a little more attention to Apple prospectively than I have recently.

At the time of publication, Bill Fleckenstein owned shares of Microsoft.

This column is a synopsis of Bill Fleckenstein's daily column on his website, FleckensteinCapital.​com, which he's been writing on the Internet since 1996. Click here to find Fleckenstein's most recent articles.

Originally published March 23, 2012