Here at the Fool, we usually don't pay attention to day-to-day price gyrations. Instead, we prefer to track each business's intrinsic value, which, by its very nature, changes a lot less frequently than Mr. Market's wild swings would have you believe.       

But at times, some price moves are just so big that investors should at least take notice -- especially when we Fools could have seen them coming.  

The big winners
With that in mind, I've summoned our Motley Fool CAPS community to highlight yesterday's biggest gainers among the stocks with a five-star rating (the highest). Also, I've included a possible explanation -- where I could find one, of course -- for each move.

So, without further ado:

Company

Yesterday's Gain

Probable Catalyst

OMNI Energy Services

7.53%

N/A

General Cable (NYSE:BGC)

7.18%

Purchase of wire-and-cable business from Freeport-McMoRan

First Marblehead (NYSE:FMD)

6.35%

Announced 10% increase in quarterly dividend

Matrix Service (NASDAQ:MTRX)

4.94%

Rise in oil prices

Chicago Bridge & Iron (NYSE:CBI)

4.93%

N/A

Did CAPS predict the pop?
The reason I selected the biggest five-star gainers, as opposed to the market's biggest overall winners, is simple: Stocks go up all the time, but unless you were able to predict the pop beforehand, what does it matter?    

Through a consensus of more than 65,000 Fools in CAPS, our community considers its five-star stocks the most likely to outperform the market. By reverse-engineering some of the arguments made for these picks, our odds of finding the next big winner will surely improve.

For example, Chicago Bridge & Iron -- which, funny as it may seem, is no longer based in Chicago, nor does it still build bridges -- has maintained a five-star rating for the past five months straight. In fact, the Netherlands-based construction company and engineer of liquid storage systems has consistently been listed as one of CAPS' top 10 best stocks. As fellow Fool Todd Wenning spells out, CBI's bullish case centers around its worldwide growth opportunities and rock-solid balance sheet.

Back in March, CAPS player dennyr3 even wrote about his firsthand experience with the company:

It will outperform over the next five years due to great management. I was taken on a tour of their new offices at Edison Plaza in Beaumont, Texas and also the new manufacturing facility in the Beaumont port. They are aggressively hiring due to their backlog, and their new shops will be full by the end of the year. Overall this is a very successful arm of the company.

CBI is up 40% since that call was made. 

The Foolish takeaway? In addition to analyzing a company's financials behind a desk, try conducting some field research on your most fruitful candidates. If you can manage to see, firsthand, the real drivers of a company's numbers through other non-conventional means, you'll have a "scuttlebutt advantage" in interpreting the numbers correctly.

Now for the losers
Of course, winning isn't everything in the stock market. Stocks go down, too -- often very, very fast.

Here are yesterday's biggest one-star decliners:   

Company

Yesterday's Loss

Probable Catalyst

Corcept Therapeutics (NASDAQ:CORT)

(17.73%)

Profit taking after recent run-up

Primedia (NYSE:PRM)

(10.71%)

Analyst downgrade

Cyberonics (NASDAQ:CYBX)

(9.35%)

N/A

Neurochem

(9.35%)

N/A

LaBranche

(8.22%)

Continued decrease in floor trading because of electronic competitors   

Did CAPS call the fall?
Whereas Fools believe five-star stocks will outperform, one-star stocks inspire the least confidence from our CAPS community. By investigating a few of the bearish arguments made for these losers, we should have a better chance of averting portfolio disaster in the future.   

Take, for instance, this Cyberonics underperform pitch found in CAPS:

Recently, the Centers for Medicare and Medicaid Services (CMS) posted a proposed National Coverage Determination (NCD) arguing that there is sufficient evidence to conclude that Vagus nerve stimulation (VNS) is not a reasonable treatment of resistant depression. This decision is bad news for Cyberonics, as the company cannot expect help from CMS to pay for post-approval studies. All these factors sum up to Cyberonics being a poor investment proposition.

The Houston-based medical device company is down 21% since CAPS All-Star NetscribeHealth penned that pitch in March. In fact, just last month, Cyberonics announced a major restructuring that will result in a workforce reduction of 12%.

The reason? Yup, you guessed it: lower sales of its VNS Therapy systems, directly attributable to CMS' non-coverage decision. Just like Netscribe described.  

CYBX's fall reminds us Fools to really analyze the extent to which a piece of bad news might hurt a business. If our analysis shows that permanent damage is likely -- as opposed to just a one-time anomaly -- we're better off kissing the stock good-bye.

The final Foolish move
Investors often focus strictly on stock price movements (or the results), without realizing that developing a proper stock-picking process counts most.

Over at Motley Fool CAPS, thousands of investors are Foolishly sharing insightful investment tips to help identify tomorrow's big movers. Over time, consistently reverse-engineering winning (and losing) stocks will help you become a more Foolish investor.

Log in to CAPS today. It's absolutely free -- and a lot of fun!

Fool contributor Brian Pacampara owns no position in any of the companies mentioned. First Marblehead is a Hidden Gems and Inside Value newsletter recommendation. The Fool has a disclosure policy is always the big winner.