Thursday's Worst Stocks in the World

Bad days. We all have them. Some of us deserve them.

Here are five stocks whose naughty ways drew investors' scorn on Thursday:

Naughty?
Well, OK, we can't exactly call these stocks naughty. There are days when five-star winners and newsletter recommendations appear here. Today, for example.

But, if you're an investor, you'll have plenty of bad days. The trick is to avoid dating -- or, worse, marrying -- your losers. That's why I listen when our 83,000-person-strong Motley Fool CAPS community of stock pickers speaks with a poor rating or a negative pitch.

Thus, here's today's list of the worst stocks in the world.

Worse
We begin with Trina Solar, which will lose it chief financial officer, Sean Shao, on March 31. Analysts cautioned not to read too much into the resignation, which, officially, is to "pursue other interests." (Aren't they all?)

Fair enough. But let's not forget that, even with all the backslapping in its press release, Trina's performance has been at best mediocre:

Accept (or deny) whatever conspiracy theory you like. Shao is leaving a company that needs as much executive talent as it can find.

Worser
Next up is Accuray, maker of X-ray therapy instruments for cancer treatment, which cut its full-year fiscal 2008 revenue outlook from $250 million to $270 million to $210 million to $230 million.

Apparently, the credit crunch is to blame. Quoting CEO Dr. Euan Thomson from a company statement:

While this was a positive quarter with respect to revenue and backlog growth, we believe that broader credit market issues are having a short-term impact on some of our U.S. customers' purchase and installation timelines, as obtaining financing has become more difficult.

That's probably true, but it's also true that Accuray faces extremely tough competition in Varian Medical Systems (NYSE: VAR) and its peers.

Varian, in particular, last week reported excellent earnings, helped in part by growth in its oncology systems subdivision, and provided a better-than-expected 2008 forecast. Coincidence? Probably not.

Worst
But our winner is Cadence Design, which offered guidance that fell far short of Wall Street estimates.

Specifically, Cadence said its adjusted profit for the first quarter will come in between $0.03 and $0.05 per share. Analysts, by contrast, expected the company to earn $0.30. Ouch.

Should we really care? Normally, no. What's troubling here is the size of the gap. Analysts aren't dumb. That they were off by this much suggests there's either a) trouble with the business, or b) trouble with the investing thesis as we've known it.

I'm betting on "a." Here's why:

Now I'll turn to our outlook for Q1 and the year 2008. As a result of our discussions with customers in Q4 and our assessment of an increasingly aggressive pricing environment that we have not seen during the past few years, we believe it is prudent to plan our 2008 business conservatively. [Emphasis added.]

Those are the words CFO William Porter in a conference call with investors and analysts on Wednesday night. While he's not explicitly saying so, my read of Porter's comments is that Cadence can't yet predict how much it'll have to lower prices to keep winning business in an increasingly difficult market for new technology.

(Gulp.)

Cadence and its apparently fragile business ... Thursday's worst stock in the CAPS world.

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I'll be back Tuesday with more stock horror stories.