Even on the market's worst days, buyout news and other short-term forces can send individual stocks up by 10%, 25%, even 50%.

For example, when Teva Pharmaceutical (Nasdaq: TEVA) offered $360 million for fellow generic-drug maker Bentley Pharmaceuticals, stock in the latter jumped 18% in a single day.

But beyond one-time blips like this one are stocks with fundamentally compelling reasons for recent momentum. The trick is to find those stocks. That's where Motley Fool CAPS comes in.

The story behind the story
CAPS is no crowd of lemmings. Its best-performing investors' opinions do more to shape each company's rating than the picks of their poorer-performing peers do. Let's use the collective wisdom of more than 95,000 CAPS investors to filter out the noise and find companies displaying strong momentum.

We'll screen for companies with a stock-price increase of at least 25% in the past month, a market cap of greater than $100 million, and a beta of less than 3. That'll keep us clear of the wild, pump-and-dump land of penny stocks.

Here's a sample of stocks our screen returned:

Company

CAPS Rating
(out of 5)

1-Month
Price Change

Sierra Wireless (Nasdaq: SWIR)

****

34.1%

SunPower (Nasdaq: SPWR)

***

49.9%

Fannie Mae (NYSE: FNM)

*

27.4%

Lennar (NYSE: LEN)

*

27.3%

Ryland (NYSE: RYL)

*

33.9%

Return data is calculated as the difference between the closing price on March 7 and the closing price on April 8, as per MSN Money's screen. Star rankings from CAPS.

Let's burrow down through this list of stocks that have thumped the market in the past month and find out the story behind the numbers.

A good day for bouncing
As we've seen once before, the housing-related stocks that everybody loves to hate these days have, on occasion, taken a brief respite from their protracted fall to surge back upward. Optimism in the beaten-down sector has returned, thanks to more Fed rate cuts, governments increased willingness to bail out beleaguered banks, and the belief of many that the worst may be over.

Homebuilders such as Lennar and Ryland have been showing positive momentum lately, despite the fact that both continue to post dismal numbers. But unlike the banks on the hook for bad mortgages, many investors see homebuilders' woes as easily fixed as those immense projects done in record time on home improvement shows -- it's just a matter of time.

With almost universal agreement among those in the sector that 2008 will bring on more of the same brutality, though, this Fool isn't inclined to wade anywhere close to the deep end of the homebuilding pool.

CAPS investors still have Lennar and Ryland in the doghouse as well -- more than 80% of CAPS All-Star investors currently give Lennar a thumbs-down. Ryland doesn't rank much better, with more than 78% of top CAPS investors voting bearishly. The bottom line is that both homebuilders maintain bottom-basement, one-star ratings, with a general sentiment that the stocks will underperform the S&P in the long run.

Answering the call
With many of the headlines in the wireless sector bemoaning the woes of some of the largest players -- Motorola and Sprint Nextel -- there are still plenty of great growth stories in the shadows. Wireless end-user equipment suppliers, like Sierra Wireless, have been profiting from a hypergrowth phase in the market for broadband modems -- those gizmos you plug into your laptop to get broadband connection anywhere your cell phone works.

In 2007, the company's annual revenue nearly doubled to $440 million, with demand sometimes outstripping the ability of the company to source components for its broadband modems. Many competitors are joining Sierra Wireless in the wave of broadband growth, though, and any indication from peers such as Novatel Wireless that the growth trend may be slowing tends to knock shares of Sierra as well.

A big question in my mind is the impact of competition from Qualcomm's (Nasdaq: QCOM) embedded Gobi platform, which is attracting many of the top laptop makers, such as Hewlett-Packard and IBM. But CAPS investors generally favor Sierra Wireless' fundamentally great prospects and good track record in the face of competition. Indeed, 92% of the 230 investors rating the company in CAPS believe it will beat the market in the future.

What's your story? Whether you buy the tale of a soaring or a souring stock, your own research is more important than collective opinions. But these collective opinions can make your due diligence a whole lot easier.

Add your take on these or any of the 5,500 stocks that our 95,000-plus investors have covered in Motley Fool CAPS. It's totally free to be a part of the community, and the payback is all for you.

The Motley Fool Stock Advisor service looks for outstanding companies poised to outpace the general market. To see all the stocks that have helped Tom and David Gardner beat the market by 37 points on average, take a free, 30-day trial.

Fool contributor Dave Mock has his own story, but there's no "happily ever after" at the end. He owns shares of Motorola and Qualcomm and is the author of The Qualcomm Equation. Sprint Nextel is an Inside Value recommendation. The Fool's disclosure policy has the momentum of a freight train but can stop on a dime.