It happens to every company sooner or later: Wall Street sets a mark for quarterly earnings, and the company misses that goal. Sometimes an earnings stumble is a signal to sell, but digging in the dirt is also a good way to find turnaround candidates while they're getting beaten down. Today, we'll meet a circuit-board manufacturer that came up a couple of resistors short, a case molder that couldn't quite close the case, and a whole drugstore full of medicine that didn't fix what ails the store.

Our first underperformer this week is Jabil Circuit (NYSE:JBL), somewhat of a local hero here in the Tampa Bay area thanks to its St. Petersburg headquarters. The maker of electronic circuit boards originally hoped to deliver $0.43 of non-GAAP earnings per diluted share this quarter, and the company's respectably large number of analysts aligned their projections to that number.

But a couple of weeks ago, the company warned that a range of $0.33 - $0.37 per share was more realistic, causing the share price to tumble more than 20% overnight. Wall Street chose to stick with the optimistic side of the new outlook, and the final result was slightly below that, at $0.36.

Revenues are growing at a healthy clip, up 34% year over year to $2.6 billion, but it's a low-margin business, and Jabil is facing some challenges these days. The litany includes inventory control problems, higher labor and materials costs, and "software problems at a tooling operation." There is also a restructuring effort going on, with some factory closings expected in the near future. On top of that, Jabil is one of the dozens of companies under scrutiny regarding stock option compensation practices.

Despite all of these dark clouds hanging over the company, Jabil caved to investor pressures and issued its first-ever quarterly dividend this quarter. Management says that the next reporting period will see significant earnings impact from the restructuring program, but net margins should subsequently rebound to the 4% range after languishing in the 3% area for a few years.

That's better than Jabil's closest competitor Flextronics (NASDAQ:FLEX), but nowhere near the breathtaking (and growing) 14% trailing-12-month net margins of Motley Fool Stock Advisor pick TTM Technologies (NASDAQ:TTMI). All things considered, Jabil looks like management has its heads screwed on straight, and it's working through current issues toward a brighter future. But I'd have to do a lot more due diligence before picking this stock over TTM, among others.

Let's move on to Deswell Industries (NASDAQ:DSWL), a small manufacturer of the plastic and metal cases that turn those bare circuit boards into the gadgets we use everyday. The Hong Kong-based company reported $0.03 of earnings per diluted share, just a fraction of the expected $0.12 and significantly below last year's $0.23 for the comparable quarter. Revenues were also down to $27 million compared to $28.7 million in 2005, and management blames the underperformance on the loss of an unspecified major customer, write-offs for obsolete product on its warehouse shelves, a "doubtful accounts receivable" entry from a customer nursing the wounds from a failed European cell phone launch, and -- stop me if you've heard this one -- increased labor and materials costs.

You might expect a small company firmly connected to the hot gadget market to grow like the dollar weeds in my backyard, but Deswell has been floundering ever since a successful second half of 2004. It seems like a customer list topped by Seiko Epson, toy and phone maker Vtech, and telecom infrastructure equipment maker Inter-Tel (NASDAQ:INTL) doesn't inspire enough new business to support a growth story, as evidenced by a mere 2.5% average earnings growth rate over the last five years.

Our last downer this time is Rite Aid Drugstores (NYSE:RAD). The company reported a solitary penny of earnings per share for the quarter, just one-third of the expected $0.03, on revenues just 2.8% above last year's at $4.34 billion. Management points to lower Medicare reimbursements and higher lease and rental costs for the store locations, along with more generic medications and less high-margin name-brand meds sold.

Rite Aid is a small fish in a big pond, and hardly causing Walgreen (NYSE:WAG) to look over its shoulder, especially not at these anemic growth rates. The company does expect to open 125 stores this fiscal year, but it had better step on it: This first quarter saw only 15 net new or relocated stores, bringing the total store count to 3,321. Even the 125-store target doesn't represent exciting growth, exactly. You might be happier leaving Rite Aid to think over its future direction before dipping your toe into these waters.

Some of these underperformers are victims of larger circumstances, while others might have only themselves to blame. It's up to you to decide which down-on-their-luck companies should be able to pull themselves up by the bootstraps, and which really are stuck in the mud. Come back next Monday, and we'll take a look at another batch of mishaps and disappointments. It'll be fun and educational. Promise.

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Fool contributor Anders Bylund owns no stock in the companies discussed, but he still remembers the Jabil booth at a college job fair many years ago. Foolish disclosure rules ensure that you know when your favorite writers are trading your favorite stocks.