Owners of UnitedHealth's (NYSE:UNH) stock have been treated to quite a plunge over the past year. Since trading at nearly $60 per share at the end of 2007, the stock has cratered, losing darn near 70% of its value. Which is far worse than the S&P Index's 42% plunge over the same period.

So why the lackluster showing? For one, the company's numbers have fallen off. Though revenue climbed 7% over the first nine months of the year, both medical and operating costs have grown faster and have taken a chunk out of the company's profits. At the same time, with the election of Barack Obama as president there is a healthy dose of uncertainty around the future of U.S. health care. Though it is possible that UnitedHealth could benefit from new health-care initiatives, Mr. Market tends to shoot first and ask questions later when it comes to uncertainty.

However, members of the Motley Fool's CAPS community have stayed very positive on UnitedHealth. More than 3,000 members have weighed in with their expectations for the stock, and over 96% of them have been bullish. None of them, however, has been quite as on-the-money when it comes to UnitedHealth as member JC4Fund, who has made two outperform calls on UnitedHealth during 2008 and has been correct on both occasions. The trick? Instead of trying to stay with the stock too long, this investor was in and out in less than a month both times and collected 40 points for the trouble.

JC4Fund is one of CAPS' All-Stars -- players with a rating of 80 or greater -- and has managed an impressive stock-picking accuracy of 64% on calls while racking up more than 660 points. UnitedHealth hasn't been this member's only great call. Here's a look at a few of this All-Star's other prescient picks:

Company

Date Picked

Call

Points

CAPS Rating (5 max)

Citigroup (NYSE:C)

8/6/08

Underperform

36

**

Abercrombie & Fitch (NYSE:ANF)

5/27/08

Underperform

33

**

General Cable

5/20/08

Underperform

32

****

Data from CAPS.

So what is this investor looking at these days? Here are a few recent CAPS calls:

Company

Date Picked

Call

CAPS Rating (5 max)

Deckers Outdoor (NASDAQ:DECK)

10/15/08

Underperform

**

Buckle

10/15/08

Underperform

**

PotashCorp (NYSE:POT)

9/2/08

Underperform

****

Data from CAPS.

While these picks may not all pan out, they could be a good place to start further research. I decided to take a closer at PotashCorp.

Going to pot?
Like many of the other commodity stocks, Potash Corporation of Saskatchewan -- which, conveniently enough, sells a fertilizer additive called potash -- looked like it was going to be able to sail through the finance-driven stock market decline. Unfortunately, what started as a finance-focused dive extended out and popped what now looks to have been a bit of a commodity bubble. This situation cratered oil and gas companies like Petrobras (NYSE:PBR), materials and metals companies like BHP Billiton, and potash slingers like PotashCorp, Mosaic (NYSE:MOS), and Intrepid Potash.

Of course you can't look to PotashCorp's recent results as any indicator of what the market is reacting to -- sales for the third quarter were more than double the prior year, while profit quintupled. The stock's 75% drop has been on the anticipation that the fourth quarter won't look so hot as prices for Potash's primary products -- potash, nitrogen, and phosphate -- will suffer as fertilizer demand drops.

Falling commodity prices have yet to convince CAPS members that PotashCorp is a stock to avoid. Nearly 4,000 members have rated the stock an outperformer, and the bullish pitches keep rolling in. A couple of weeks ago, CAPS All-Star teyink logged in with these thoughts:

I am going to say outperform for now as I think agriculture will lead commodities out of this crash. Although, I am worried that some farmers won't have access to credit that is needed to plant in the spring. This would drive grain prices up, but would also reduce the demand for potash. It would also have the nasty side effect raising food prices for everyone even as wages are declining and unemployment is rising. I will end this pick if I think that will happen. I'm guessing the government would step in and make sure farmers have access to credit so that we don't start massive global starvation.

So what's your take on PotashCorp? Will it find a way to bounce back or will Mr. Market continue grinding it into the ground? Get in the action by clicking over to CAPS. It's absolutely free and already has more than 120,000 stock pickers chipping in to find the best stocks out there.

More CAPS Foolishness:

Petroleo Brasileiro is a Motley Fool Income Investor pick. UnitedHealth Group is an Inside Value and Stock Advisor selection. The Fool owns shares of UnitedHealth Group. Try any of our Foolish newsletters today, free for 30 days

Fool contributor Matt Koppenheffer is cutting back to one meal per day in preparation for the big Turkey Day. He owns shares of UnitedHealth, but does not own shares of any of the other companies mentioned. The Fool's disclosure policy wouldn't know potash if it bit her on the ankle.