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 ...
Wall Street wunderkind JMP Securities spun on the proverbial dime this morning, upgrading shares of Marvell Technology (NASDAQ:MRVL) all the way from "market underperform" to "market outperform." The shares are reacting just as you'd expect in response to a 180-degree reversal like this -- rocketing as much as 15% on a day when Wall Street is barely out of the loss column.

Of course, Marvell shareholders can probably thank Texas Instruments (NYSE:TXN) for at least part of those gains. TI's prediction of better-than-expected profits yesterday has also given a market cap boost to PC parts-makers Intel (NASDAQ:INTC), NVIDIA (NASDAQ:NVDA), and Advanced Micro Devices (NYSE:AMD). And while not all of these firms compete directly with Marvell, they all share the common trait of making PC innards.

In fact, about the only "chip" firm sitting out the rally is Qualcomm (NASDAQ:QCOM) -- up barely a couple of percent, which is a bit strange seeing as TI attributed its renewed optimism to expectations of growth in the market for smartphones.

But getting back to Marvell and JMP ... in upgrading the stock, the analyst suggested that Marvell's biggest prospects are in "the PC channel," where "netbooks generating healthy unit volume demand for [hard disk drives]," and a "benign refresh" with Apple's (NASDAQ:AAPL) new iPhone. All of this has JMP upping its expectations both "near-term and out-year." But should you?

Let's go to the tape
Perhaps not. You see, JMP isn't really a wiz at this stock-picking thing. According to CAPS, where we've been monitoring its progress for nearly three years now, JMP is in fact one of the worst stock pickers. The analyst ranks in the bottom 20% of investors we track, and gets only about 44% of its recommendations right.

And if you think that's bad, get a load of JMP's record in the semi-sphere:

Stock

JMP Says:

CAPS says:

JMP's Picks Beating (Lagging) S&P By:

National Semiconductor

Outperform

**

5 points -- 2 picks

Texas Instruments

Underperform

****

(16 points) -- 2 picks

AMD

Underperform

**

(72 points) -- 2 picks

Micron Technology

Underperform

**

(112 points) -- 2 picks

Turns out, as bad as JMP is at picking stocks generally, it's absolutely horrible at picking semi-stocks, getting less than one in three of its picks right.

Buy the numbers
That said, as unimpressed as I am with JMP's performance, I must admit I'm intrigued by today's pick. You see, while at first glance Marvell is a mess -- 187 P/E, long-term growth pegged at less than 15%, etc., etc. -- my review of the firm's cash flow statement suggests things may not be nearly as bad as they appear.

For while Marvell's been lagging a bit in the GAAP game lately, the firm continues to churn out beaucoup free cash flow regardless. The last 12 months have seen Marvell generate nearly $650 million in free cash flow. Divide that into its enterprise value, and it becomes apparent that this firm is selling for just over nine times its free cash profitability.

Foolish takeaway
If Marvell achieves anything near the growth rate Wall Street projects for it, that seems to provide a sizable margin of safety for investors entering the stock -- even after today's run-up. Whether that's a big enough cushion to justify aligning your portfolio with JMP's advice, though ...

Well, you pays your money, you takes your chances. For my part, though, I'm intrigued.

Apple and NVIDIA are Stock Advisor recommendations. Intel is an Inside Value selection. The Fool has sold puts on Intel.

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. 953 out of more than 135,000 members. The Motley Fool's disclosure policy performs well in any market.