Thursday's Worst Stocks in the World

Bad days. We all have them, but 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. But none of them gets much love from our 65,000-player-strong Motley Fool CAPS community of amateur and professional stock-pickers.

To the contrary -- when it comes to these stocks, CAPS investors have gone thumbs-down more often than film critic Roger Ebert. They don't believe any of these stocks are worth owning, and they even think some may be worth shorting.

Which of today's candidates is worst? Read on, dear Fool.

Worse
Penwest Pharmaceuticals kicks off today's list. Why? Generic drug specialist Impax Labs is challenging its patent for the pain reliever Opana ER, held in conjunction with Endo Pharmaceuticals (NASDAQ:ENDP).

But Endo may get hurt the most if Impax succeeds. Forbes reports that, earlier this week, the FDA refused to approve Endo's drug for menstrual migraines. Oh, goody.

Worser
Wet Seal makes our list for its lousy comps report. "Comps," folks, is investorspeak for "same-store sales." Retail followers like to see improving sales at stores open for more than a year. Good comps often means either (a) a good product, (b) a loyal customer base, or, best of all, (c) both.

Wet Seal gets (d) none of the above. Management expects comps to dive anywhere between 7.5% to 8.5%, a huge swing from the earlier projected range of a 1% decline to a 3% gain. Yuck.

Worst
But our winner is Isilon Systems, a Sequoia Capital company that, frankly, ought to be doing better. (Investors certainly expected more.)

For those who don't know, Isilon makes storage devices that can more easily handle unstructured data such as email or contracts. That may not sound like much, but trust me, it's huge. The vast majority of data that companies produce can't easily fit into a database.

Nevertheless, on Thursday, Isilon lowered its forecast for third-quarter earnings to below what the pinstriped-suit crowd had expected. And just like that, shareholders found their positions 19% lighter. Eat that, Jenny Craig.

Or don't. There's little tasty about Isilon, as far as our CAPS contingent is concerned.  All-Star NetscribeTech explains:

The company competes with big boys such as Hewlett-Packard, Hitachi, IBM (NYSE:IBM), and Sun Microsystems among others. Thus, beyond [its] ability to scale up, [success] would depend [on its ability] to create [a] superior value proposition. The other issue the company may face would be slower acceptance of the new paradigm. [Emphasis added.]

Let's see. What would be a sign of slower acceptance? A poor forecast, perhaps? Isilon Systems ... today's worst stock in the CAPS world.

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See you back here tomorrow for more stock horror stories. Or, if you don't like this feature, please let me know here.