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, shares in Advantage Energy Income Fund jumped 15.3% one day last week when shareholders approved a conversion from a trust to a corporation.

But beyond less-predictable events like that 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 members' opinions do more to shape each company's rating than the picks of their poorer-performing peers. Let's use the collective wisdom of more than 135,000 CAPS members to filter out the noise and find companies offering strong momentum.

We'll use CAPS' handy stock screening tool to quickly zero in on companies with a stock price increase of at least 20% in the past four weeks, a market cap of greater than $100 million, and a beta of less than 3. Below is a sample of stocks that our screen returned. If you'd like, run this screen yourself -- just keep in mind that results may change as the market does.

Company

CAPS Rating
(Out of five)

4-Week
Price Change

Oshkosh (NYSE:OSK)

****

47.1%

Cray (NASDAQ:CRAY)

***

21.4%

Ivanhoe Mines (NYSE:IVN)

**

22.6%

Source: Motley Fool CAPS. Price return from June 12 through July 10.

Keep on truckin'
Heavy industry manufacturer Oshkosh recently won a $1 billion contract from the U.S. government to build MRAP all-terrain vehicles for the Army to use in Afghanistan. The company beat out bidders like Force Protection, General Dynamics (NYSE:GD), and Navistar, but could subcontract work to them to help with production. The initial deal calls for 2,244 M-ATVs, but could reach 10,000, bringing in up to an additional several billion dollars over the life of the program. The deal caused a boost in Oshkosh's shares and triggered a rash of analyst downgrades and upgrades within the sector. One analyst called the deal a "game changer" for Oshkosh, but some CAPS members thought the company was solid before it won the contract, which is just icing on the cake. That's a lot of icing, though, and 94% of the 774 CAPS members rating Oshkosh expect it to outperform the market.

Supercomputer to the rescue
One of Cray's supercomputers, the XT5 Jaguar system at the Oak Ridge National Laboratory in Tennessee, continued to hold the No. 2 spot on the updated Top 500 list of the world's fastest supercomputers. The super number-cruncher is just a whisker behind one built by IBM (NYSE:IBM). The list includes other top system builders like Hewlett-Packard (NYSE:HPQ) and processor makers like Intel and Advanced Micro Devices (NYSE:AMD), making it a marketing tool that helps tout a company's name to potential clients. Cray's XT5 series of supercomputers has created momentum for the company in recent quarters, and it recently beefed up the series with AMD's latest salvo against Intel -- its Six-Core Opteron processors.

The share price has multiplied a few times in value so far this year as the company reported strong revenue in recent quarters. But management still expects a small operating loss for 2009 and says revenue could fluctuate widely depending on how business goes. Many of Cray's customers are government and educational research labs in a fairly insulated sector, but that also limits the company's growth opportunities. At this point, only a lackluster 83% of the 103 CAPS members rating Cray think the company will continue to outperform the market.

And you?
What's your story? Whether you buy the tale of a stock that's soaring or souring, 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 other 5,300 stocks that our 135,000-plus members have covered in Motley Fool CAPS. It's totally free to be a part of the community, and the payback is more than worth it.

The Motley Fool Inside Value team looks for oversold stocks that are selling at bargain prices well below their intrinsic value. To see the full list of companies recommended today, take a free 30-day trial.

Fool contributor Dave Mock has his own story, but there's no "happily ever after" at the end of it. He owns shares of Intel. General Dynamics and Intel are Inside Value selections. The Fool's disclosure policy has the momentum of a freight train, but can stop on a dime.