At The Motley Fool, we poke plenty of fun at Wall Street analysts and their endless cycle of upgrades, downgrades, and "initiating coverage at neutral." So you might think we'd be the last people to give virtual ink to such "news." And we would be -- if that were all we were doing.

But in "This Just In," we don't simply tell you what the analysts said. We'll also show you whether they know what they're talking about. To help, we've enlisted Motley Fool CAPS, our tool for rating stocks and analysts alike. With CAPS, we track the long-term performance of Wall Street's best and brightest -- and its worst and sorriest, too.

And speaking of the worst ...
What with the holiday season and all, I hate to be the bearer of bad news today, but considering how investors are reacting to news of Capital One's upgrade of ATP Oil & Gas (NASDAQ:ATPG), a warning is in order: I may have been wrong.

One month ago, almost to the day, I argued in a column entitled "Rocket Stock or Dud?" that ATP looked every bit the "buy" that Capital One now says it is. The stock sold for just a little over two times book value. Its P/E sat at eight, relative to a projected growth rate of 15% per annum over the next five years. Best of all, the firm's enterprise value seemed to discount the value of its proven oil and natural gas reserves by a factor of 2 times or more. Of course, all this was before Capital One chimed in.

Let's go to the tape
Yesterday morning, Capital One awoke bright and early from its tryptophan-induced weekend slumber, groggily declaring its intention to upgrade ATP. Muttered CapOne: "ATPG shares have underperformed the group over the past month [but] Valuation metrics should begin to improve as we move into 2010."

Problem is, CapOne hasn't been terribly accurate on such oil and gas predictions in the past, guessing wrong nearly twice as often as right:

Stock

Capital One Says

CAPS Says

Capital One's Picks Beating
(Lagging) S&P by

Chesapeake Energy (NYSE:CHK)

Outperform

*****

(39 points)

XTO Energy (NYSE:XTO)

Outperform

*****

(14 points)

W&T Offshore (NYSE:WTI)

Outperform

*****

1 point

The banker has had better luck within the Energy Equipment and Services area of the oilpatch -- but only a little better, scoring 37.5% for accuracy here:

Stock

Capital One Says

CAPS Says

Capital One's Picks Beating
(Lagging) S&P by

National Oilwell Varco (NYSE:NOV)

Outperform

*****

32 points

Patterson-UTI (NASDAQ:PTEN)

Outperform

****

(37 points)

Transocean (NYSE:RIG)

Outperform

*****

(<1 point)

With a record like this one, a Fool can be forgiven for wondering: How likely is it that this time, CapOne's ATP pick will turn out A-OK?

In recommending an investment in ATP this week, CapOne puts a lot of faith in the likelihood of an imminent production increase: "Production should double to ~200 MMcfe/d by 3Q10 ... with the start-up of Telemark around the end of 1Q10 ... Liquids accounted for about 56% of ATPG's 3Q09 production, and this % should increase with Telemark (initial production expected to be 80% oil)."

So in this respect, at least, the bull thesis for ATP got stronger this week. Problem is, it's also gotten weaker since I first reviewed the stock last month. While the assets and book value still look attractive, ATP's loss-making third-quarter report has pushed trailing earnings way down -- and as a result, the stock's P/E way up. Whereas just one month ago, ATP could be accurately described as trading for "eight times trailing earnings," today the P/E has doubled -- to 16.

Foolish takeaway
Now of course, it's nearly impossible for a company to lose half its intrinsic value in a month, and in fact, by the time ATP admitted to losing money on November 5, the money had already been lost -- it just wasn't showing up on the financials, or inflating the P/E, yet. Similarly, the assets ATP had one month ago are still there. The book value's still there -- in short, much of the bull thesis in favor of this stock still remains intact.

All that's really changed, I suspect, is the tally of investors who think this bull has horns. We know what Capital One thinks -- now's your turn. Click over to Motley Fool CAPS now, and tell us whether you think ATP is still worth owning.

National Oilwell Varco is a Motley Fool Stock Advisor pick. Chesapeake Energy is a Motley Fool Inside Value selection. W&T Offshore is a Motley Fool Hidden Gems recommendation. The Fool owns shares of Chesapeake Energy and XTO Energy.

Fool contributor Rich Smith does not own shares of, nor is he short, any company named above. You can find him on CAPS, publicly pontificating under the handle TMFDitty, where he's currently ranked No. 818 out of more than 145,000 members. The Motley Fool has a disclosure policy.