Individual stocks can surge 10%, 25%, or even higher in a short period of time. And they can fall just as far, just as quickly. For example, shares in Radio Shack (NYSE:RSH) turned south and plummeted 24% on Tuesday after the company reported a 39% drop in quarterly profit.

Big drops in share price can sometimes signal material defects or new risks. But at other times, they're simply pullbacks along with the larger pessimism facing the market today. Fortunately, we have Motley Fool CAPS, a great resource to help us understand the larger picture behind big price drops.

Is the sky falling?
CAPS contains more than just the crowd's opinions. Its best-performing members' votes count more in shaping each company's rating than do the picks of their poorer-performing peers. That way, investors can intelligently use the collective wisdom of more than 125,000 CAPS members to make better decisions.

We'll use CAPS' handy stock screening tool to quickly zero in on companies that have been slashed by at least 25% in the last four weeks, and which have a market cap greater than $100 million and a beta of less than 3. If you want to run this screen for yourself, please do -- just keep in mind that the results will update with the market.

Company

CAPS Rating
(5 stars max.)

4-Week
Price Change

UBS (NYSE:UBS)

*

(26%)

Geron (NASDAQ:GERN)

**

(29.1%)

StemCells (NASDAQ:STEM)

**

(27.2%)

Research In Motion (NASDAQ:RIMM)

***

(27%)

General Electric (NYSE:GE)

****

(25.1%)

Source: Motley Fool CAPS. Price return from Jan. 30 through Feb. 24.

UBS
According to the Swiss National Bank, total deposits held by Swiss banks fell by 27% in 2008, with leading banks like UBS and Credit Suisse reporting large outflows of foreign money. Now the country's safe offshore status is being threatened and investors are growing more concerned about a civil lawsuit by U.S. tax authorities against UBS seeking data on 52,000 Americans believed to be shirking tax obligations. With the controversy hanging over UBS, it's little wonder then that only 59% of the 818 CAPS members rating UBS expect it to outperform the market.

Geron and StemCells
Shares of companies related to stem-cell research soared last month when Geron became the first company to gain FDA clearance for early stage clinical trials for stem-cell testing for the treatment of severe spinal cord injuries. Also, there's been a lot of anticipation building over an expected lifting of a ban on federal funding for embryonic stem-cell research, which many investors believe will open the floodgates of opportunity for companies like Geron and StemCells.

But shares in both companies have quickly retraced their recent gains, and some CAPS members feel that shares may have gotten ahead of themselves. Geron has a long way to go before its developments see commercial use, and companies like StemCells don't have a direct tie to embryonic therapies. But while it may be true that a potentially lifted stem-cell funding ban will actually do little to directly help the companies, many CAPS members still see immense long-term potential in both of the cutting-edge therapy developers. In CAPS, 84% of the 516 members rating Geron are bullish, while 88% of those rating StemCells expect it to beat the market.

Research In Motion
RIM shares recently took a dive after the BlackBerry maker warned about coming in on the low end of its earnings guidance, despite projecting more net new subscribers than previously targeted. Shares have also been under pressure since several RIM executives recently settled charges with the SEC and Ontario Securities Commission over backdating stock options, a practice that's brought scrutiny to many companies like Apple (NASDAQ:AAPL) and Home Depot in the past. With its stock well off its highs, roughly 83% of the 4,884 CAPS members rating Research In Motion expect it to beat the S&P.

General Electric
While its other units remain profitable, GE's finance unit is dragging the business down. Shares have recently fallen to lows not seen in more than a decade on fears of more losses buried in its financial unit. And while a Deutsche Bank analyst recently noted the high long-term earning potential of GE Capital, he also acknowledged the risk of the company possibly slashing its dividend to cover unrealized losses. At this point, 93% of the 12,886 CAPS members rating GE remain bullish on its long-term potential and expect it to outperform the market.

Ultimately, whether or not you believe a fall in any stock is warranted, your own research is more important than collective opinions. CAPS can help you quickly focus your due diligence, and even point out potential pitfalls you may not have seen.

Add your take on these or any of the nearly 5,400 stocks that 125,000-plus members have covered in Motley Fool CAPS.

The Motley Fool Stock Advisor service looks for companies with strong management poised to beat the market over the long haul. To see all the stocks that have helped Tom and David Gardner beat the market by 31 points on average, take a free 30-day trial.

Fool contributor Dave Mock habitually looks for silver linings in even the darkest of clouds. He owns no shares of companies mentioned here. Apple is a Motley Fool Stock Advisor pick. The Fool's disclosure policy is made of sugar and spice and everything nice.