Value investors are always looking for some sort of catalyst to propel an unappreciated stock from the basement to the penthouse. But sometimes a ridiculously low price can be its own catalyst.

That certainly appears to have been, in part, the case with

Computer Network Technology

(CMNT)

. Last week,

I explained that the company was one of the least expensive major tech companies on the

Nasdaq

, selling for less than book value despite seemingly decent prospects.

That prompted email from readers who accused me of not knowing what I was talking about. With the stock in the dumps, one correspondent captured the major market sentiment with this comment: "Yes, this stock looks cheap, but it is about to get cheaper." The reader pointed out a few negative data points with the company, then added that he would never invest a dime in the firm because "management ... has a proven track record of disappointing investors and employees."

Well, that's exactly how a stock ends up valued less than book. But very often, the point of maximum angst for even the most knowledgeable holders is the turning point. As the mood for storage-area networking stocks improved later in the week, shares of Computer Network jumped by more than 11%.

But that was only a prelude to Monday's action, when the company's shares were gunned another 17% in after-hours trading on the heels of a relatively weak earnings report that, after excluding a bunch of charges, wasn't quite as bad as many analysts and traders expected. This reaction was a good example of bad mood trumping the numbers for a period just long enough for value players to take advantage.

Another example is still playing out in the shares of

Mas-Tec

(MTZ) - Get Report

, which I previously cited as a value on

Aug. 18, when shares went for $5.48, and

June 3, when shares were $4.10. The company has still not released its financial reports for the past three quarters, but the price had gotten so unreasonably low that it has continued to levitate from the buying pressure of value hunters. Last week the stock peaked above $9.10 before slipping back in the past couple of days to around $8.00.

According to my valuation model, the cheapest stocks in the

S&P 500

today that have at least modestly good prospects are

Fiserv

(FISV) - Get Report

,

SunGard Data Systems

(SDS) - Get Report

), Cendant

(CD)

,

Reebok International

(RBK)

and

Hewlett-Packard

(HPQ) - Get Report

.

Each is weighed down by price/multiples that are chintzier than their peers and the broad market, and are underwater in trading this year. But like Computer Network Tech and Mas-Tec, their time in the sun could come in the next six months -- and they will catch bears and short-sellers by surprise. For as you have seen, even without huge improvement in their business, a low price alone can spur buyers to action.

P.S. Don't forget -- now is a great time to get in on bargain stocks before the prices go up. Get my picks with a

free trial

to TheStreet.com Value Investor.

Please note that due to factors including low market capitalization and/or insufficient public float, we consider Computer Network Technology to be a small-cap stock. You should be aware that such stocks are subject to more risk than stocks of larger companies, including greater volatility, lower liquidity and less publicly available information, and that postings such as this one can have an effect on their stock prices.

At the time of publication, Markman was long Computer Network Technology, although positions may change at any time.

Jon D. Markman is publisher of StockTactics Advisor, an independent weekly investment research service, as well as senior strategist and portfolio manager at Pinnacle Investment Advisors. He also writes a weekly column for CNBC on MSN Money. While Markman cannot provide personalized investment advice or recommendations, he welcomes column critiques and comments at

jon.markman@thestreet.com.

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