Even on the market's worst days, headlines and ticker feeds tout soaring stocks. Some juicy rumor or biotech wonder drug seems to be reason enough for a stock to climb 10%, 25%, even 50% -- sometimes in a single day. Sometimes the companies are familiar, but many are names and stories entirely unknown to investors.

Often, news of a buyout offer that investors didn't anticipate sends a stock rocketing. For instance, business intelligence software maker Cognos' (NASDAQ:COGN) $339 million offer for Motley Fool Rule Breakers recommendation Applix (NASDAQ:APLX) caused Applix's stock to surge more than 22% in a single day. But beyond these somewhat unpredictable surges, there are stocks out there with a fundamentally compelling story behind their recent momentum. The difficulty comes in sifting through the daily trading and news-driven gyrations to find them.

Luckily, there's help right at your fingertips. Motley Fool CAPS is a great tool not only for finding and screening stocks, but also for getting a quick read on the fundamental stories behind them. In addition, investors can quickly see just who -- from the big names on Wall Street that we track to the regular Joes on Main Street -- is bullish or bearish on the company, and why.

The story behind the story
Let's dig right in, using the collective wisdom of more than 65,000 CAPS investors, to look past the splashy news and find companies showing strong recent momentum.

We'll screen for stocks showing at least 25% price appreciation in the past month. Then we'll weed out stocks with less than a $100 million market capitalization and those with a beta greater than 3. This will help keep us out of the wild, pump-and-dump land of penny stocks. Here, then, is a broad sampling of stocks that our screen returned today.

Company

CAPS Rating (out of 5):

Price Change Last Month:

GigaMedia (NASDAQ:GIGM)

*****

43%

Cal-Maine Foods (NASDAQ:CALM)

****

29.6%

Pozen (NASDAQ:POZN)

**

39.2%

Avanir Pharmaceuticals (NASDAQ:AVNR)

*

34.6%

Accredited Home Lenders (NASDAQ:LEND)

*

76.9%

Data from MSN Money. Star ranking from CAPS. All data as of Sept. 11.

Now let's sift further through this list of stocks that have thumped the market over the past month and find out why they've performed so well.

The method behind the madness
CAPS contains a searchable record of investors' opinions and comments about a company's fundamentals, value, and prospects at any given time. Users can see what other investors were saying about a company before a huge surge in price, and whether those investors still favor it after the run-up. A company's star ranking also has a history, showing whether that company has been rising or falling in the investing community's favor.

Lest you think that keying off CAPS ranks is equivalent to following a crowd of lemmings, note that the CAPS system weighs the opinions of the best-performing investors more heavily than those who haven't done so well. Thus, a company's ranking is influenced more strongly by investors who have already proved themselves better than the average dart-throwing monkey.

Chicken or the egg?
Chances are good that the last egg you enjoyed for breakfast came from the largest shell egg distributor in the U.S., Cal-Maine Foods. The company has been laying a few golden eggs for investors lately, with shares popping up more than 25% in the past month. But these gains came after a roller-coaster ride up and then back down a similar amount in only the last few months. While the egg-production industry is very mature, it tends to be quite volatile, since egg and feed prices fluctuate dramatically.

Shares in Cal-Maine peaked in July, when the company announced a strong close to its fiscal year 2007 by reporting a 25% increase in revenue and net income of $36.7 million. Even though corn prices have been rising dramatically thanks to demand for ethanol fuels, the company benefited from increased egg prices and sales of specialty egg products, more than making up for the increased costs. A total of 134 of the 139 CAPS players rating the company are voting that it will beat the S&P going forward, putting faith in the company's growth strategy of acquisitions and increased sales of specialty eggs. Investors also like the high level of insider ownership by CEO and Chairman Fred Adams and the company's track record of efficient operations.

Grab the buckets ...
With all the mess unraveling in the subprime-mortgage business, you wouldn't expect to see stock in lender Accredited Home Lenders soaring more than 75% in a month. Like many other subprime lenders, Accredited has been showing all the signs of a sinking ship -- closure of retail outlets, massive layoffs, hundreds of millions in margin calls and the resignation of its CFO. And as the rats have been scrambling upward toward drier ground, the company put down a trail of cheese to help them find their way out with an ominous "going concern" warning in its annual report.

But the recent rise in shares and (at least temporary) reprieve for the rats came on renewed hope that a deal for the carcass of the company is still possible with financial fund Lone Star. Investors are betting that even a lower offer given by Lone Star, and maybe the desperate bailout proposed by President Bush, will help the company avoid bankruptcy. As I recall, rats can be amazingly good swimmers, but time is running short with no land in sight -- more than 80% of CAPS All-Stars are betting against the rats and believe Accredited is set to underperform the S&P going forward.

What's your story?
Ultimately, the only story that counts is your own. Whether you buy the story of a soaring or souring stock, your own research is more important than collective opinions. But thankfully, these collective opinions make an individual's job of due diligence much easier.

So step right up and chime in with your own take on these or any of the more than 5,000 stocks that investors have covered in Motley Fool CAPS. It's totally free to be a part of this story, and the payback is more than worth it.

The average pick in the Motley Fool Rule Breakers newsletter service is up 29.1% vs. the S&P gain of only 14.4%. To see what market-beating stocks David Gardner is picking today, take a free 30-day trial.

Fool contributor Dave Mock has his own story, but he won't bore you with the details. He owns no shares of the companies mentioned here. Dave is the author of The Qualcomm Equation. Applix is a Rule Breakers recommendation. GigaMedia is a Global Gains pick. The Fool's disclosure policy has the momentum of a freight train but can stop on a dime.