I'm always looking for a good deal, whether that means buying an extra box of Golden Grahams when they're on sale, or pouncing on undervalued stocks. The idea that anybody would sell a stock for less than its worth may seem silly, but legendary value investor Ben Graham (no relation to the cereal) tells us, by way of allegory, how we can look out for these situations.

In The Intelligent Investor, Graham introduces readers to a wacky chap named Mr. Market. He pays you house calls on a daily basis, offering to sell you interests in businesses he owns, or to buy from you interests in businesses you own. Sometimes, Mr. Market will show up at your door very excited, offering you premium prices for your holdings. At other times, he'll be inconsolably depressed about the future, and he'll offer to sell you what he has for as low as pennies on the dollar.

To find some of the stocks that Mr. Market is depressed about, I've turned once again to The Motley Fool's CAPS investor community. Each of the companies below had been given a five-star rating (the highest) by our community of investors just 30 days ago:

Stock

30-day return

One-year return

Current CAPS rating

Dow Chemical (NYSE:DOW)

(44.6%)

(78.5%)

****

Navios Maritime (NYSE:NM)

(23.1%)

(78.7%)

****

Valero Energy (NYSE:VLO)

(18.7%)

(66.7%)

*****

Bucyrus International (NASDAQ:BUCY)

(17.8%)

(74%)

*****

Kraft Foods (NYSE:KFT)

(17.3%)

(21.9%)

****

Vaalco Energy (NYSE:EGY)

(16.7%)

36.1%

*****

UnitedHealth Group (NYSE:UNH)

(13.7%)

(49.5%)

*****

Data from Motley Fool CAPS as of Feb. 24.

As the table shows, these stocks are all still very well-regarded by the CAPS community, despite their underperformance over the past month. While these are not formal recommendations, they could be a great place to kick off some further research. I'll even get you started with some thoughts on Valero Energy.

Why so blue?
After being colder than a polar bear's toenail for darn near two years, refining stocks started to see some life after bottoming out back in November. Refining margins had been squeezed to the point of squealing, and oil seemed unstoppable -- that is, until it no longer was. Gas prices collapsed with crude oil prices, but in the process, that all-important refining margin found some breathing room again.

Though both gas prices and crude prices will depend on whether our crazy economy can pick its way through the rubble of the financial industry, investors started getting more positive on Valero and the rest of the refining industry over the past three months. So why the drop? Economic concerns likely have something to do with it, but it also may just be a pullback from the gains -- from the November trough to the late-January peak, the stock was up more than 80%.

What the bulls say
As Valero's stock picked up steam, its CAPS rating actually fell into four-star territory. The recent price drop, however, has brought more bulls into the picture, and the stock's 4,121 outperform ratings today have helped elevate it back to a perfect five stars.

If we take CAPS players at their word, there doesn't seem to be a bad reason to own Valero. CAPS All-Star TMFDeej recently chimed in to say: "Crack spreads are huge and getting bigger in the near future. Plus it has a decent yield." I wouldn't disagree with that take on either front.

Meanwhile, drake7 approached Valero from a supply/demand perspective:

This stock is solid and just suffering from the general global malaise. Since we are not going to be building refineries anytime soon under a democratic administration this stock will hit 30$ by years end or sooner.

Though I don't tend to favor such precise timelines for stock movements, I think drake7 was exactly right about new refinery building.  Everybody wants their gasoline, but no one wants a refinery in their back yard. Slow growth in refining capacity means that when demand picks back up, refiners will be sitting pretty.

Do you think the recent drop has created a good buying opportunity? Or will Valero see another squeeze on its refining margins? Head over to CAPS and share your thoughts with the other 125,000 community members. Even if you'd prefer to pass on Valero, you can check out a couple of the other stocks listed above, or any of the 5,400 stocks that are rated on CAPS.

More CAPS Foolishness:

Kraft Foods is a Motley Fool Income Investor pick. UnitedHealth Group is a Motley Fool Inside Value recommendation, a Motley Fool Stock Advisor selection, and a Motley Fool holding. Try any of our Foolish newsletter services free for 30 days.

Fool contributor Matt Koppenheffer does not own shares of any of the companies mentioned. You can check out what Matt likes in CAPS by visiting his CAPS portfolio. The Fool's disclosure policy offers you one Schrute buck for reading this far.