"The bigger they are, the harder they fall." It's the worst nightmare of every investor in today's market -- buying a rocket stock just before it takes a nosedive.

Now, I readily admit that sometimes, stocks rise for a reason. But sometimes, the rise becomes the reason. No matter how often we caution them not to, investors do have a habit of buying "hot" stocks, and trusting momentum to keep 'em moving up.

Problem is, if the price goes up too much, even a great company can turn into a lousy investment. Below, I've listed a few stocks that may have done just that. According to the smart folks at finviz.com, these companies' shares have more than doubled since the beginning of this year, and they just might be ripe to fall back to earth.

Companies

Recent Price

CAPS Rating (out of 5):

Spirit AeroSystems (NYSE:SPR)

$20.42

*****

Baidu (NASDAQ:BIDU)

$418.10

**

Nordstrom (NYSE:JWN)

$36.05

**

Sun Microsystems (NASDAQ:JAVA)

$8.36

**

Sirius XM Radio (NASDAQ:SIRI)

$0.61

**

Companies are selected by screening for 100% and higher price appreciation year to date on finviz.com. Five stars = highest possible CAPS rating; one star = lowest. Current pricing provided by Yahoo! Finance. CAPS ratings from Motley Fool CAPS.

Each of these stocks has already won big this year, but how many of them can keep on winning? Our 145,000 CAPS members don't seem too optimistic about most of these companies continuing their streak into the new year. However, there is one stock that we believe can keep flying higher.

Spirit AeroSystems
The company enjoys strong support from some of CAPS's very best investors, and has for some time. As far back as May, for example, CAPS All-Star MJKpayday was arguing that "this major supplier of aircraft systems will outperform the S&P in the coming years. The industry allows for plenty of growth, It's price is low considering it's mostly healthy balance sheet and earning potential, and management is responsible."

Fellow All-Star freestate80 agrees, adding in June: "With 787 nearing production, this is an indirect play on the 787."

And not just the 787. Yet another of our ace investors, dockofthebay, recently wrote a long list of the high-profile projects the company is involved with, ranging from the 787 to the "737 ... AC-130U Gunship ... Raytheon [NYSE: RTN] Hawker 800XP ... Airbus A320, A330, A340 and A380 ..." and on and on.

In short, name any airplane, and there's a pretty good chance that Spirit AeroSystems built at least part of it. That said, there should be no doubt in anyone's mind what's driving the latest run-up in its stock price. Boeing's (NYSE:BA) long-awaited 787 Dreamliner could fly as early as Tuesday. And while success here would do great things for Boeing, arguably it could bode even better for suppliers like Spirit AeroSystems, which has spent many a cash-burning year waiting for Boeing to get its act together -- and its test plane off the ground.

Although the company continues to report "profits" as GAAP accounting standards count such things, the past three years have cost it close to half a billion dollars, as Spirit AeroSystems waited for the green light to begin producing 787 parts. Today, by all accounts, we're within a year of the first 787 delivery -- at which point the company might begin to replenish its depleted treasure chest.

So is now the time to make a bet on Boeing, and Spirit AeroSystems? Personally, I have my doubts about Boeing's ability to meet its tight deadline for Federal Aviation Administration clearance on the plane this year. Accordingly, I'd discount Spirit AeroSystems' chances of receiving parts orders as soon as promised.

Time to chime in
Between its hefty debt load, its history of burning cash, and its not-cheap P/E ratio in the high teens, I wouldn't rush out right now to load up on Spirit AeroSystems shares. To the contrary, if you've benefitted from the remarkable run-up in the stock price this year, I would seriously consider taking some profits off the table -- "selling the news," as the experts say.

But that's just me. Just because I think Spirit AeroSystems is a dud doesn't mean you have to agree. (In fact, I rather suspect there are some Fools over at Motley Fool Hidden Gems who'd disagree with me pretty strongly.) Here at the Fool, we're open to all opinions on the stocks we discuss -- and we'd love to hear yours. Click on over to Motley Fool CAPS now and tell us what you think.

Fool contributor Rich Smith owns shares of Boeing. You can find him on CAPS, publicly pontificating under the handle TMFDitty, where he was recently ranked No. 764 out of more than 145,000 members. Spirit AeroSystems Holdings is a Motley Fool Hidden Gems selection. Baidu is a Motley Fool Rule Breakers recommendation. The Fool disclosure policy has no problem helping out Fool analyst Dan Dzombak in his battle with unwanted syndicators.