NEW YORK (TheStreet) -- "If at first you don't succeed, try, try again" is one of my favorite childhood proverbs. As an investor, however, that advice can be a recipe for financial ruin. And for those who have placed their faith in Joy Global (JOY) , a manufacturer and servicer of coal-mining equipment, it appears that it's past time to stop trying.

To call Joy Global stock a disappointment would be an understatement. Not only is it down more than 16% in 2015, but expand the horizon to five years, and it's been a bloodbath. But there remain investors who follow the proverb above, so new money comes in with each new low made by JOY stock. After each decline, the price looks cheaper, luring investors with the idea that a bottom has been found. Instead, things keep getting worse.

Although Joy Global, headquartered in Milwaukee, is profitable, the company -- like peers Cliffs Natural Resources (CLV)  and Console Energy(CNX) - Get Report -- operates in a coal industry that is suffering from poor economics. That is to say, there is too much supply and too little demand to make coal-related stocks worthwhile investments.

So ahead of Joy Global's second-quarter earnings results -- due out Thursday before the opening bell-- do not touch these shares. Granted, at 12 times earnings, there's some implied value here, especially when compared to the average S&P 500 (SPX) stock's P/E of 21. But in this case, "cheap" is cheap for a reason.

During the last five years, Joy has been cheap and it still hasn't kept the so-called "smart money" from buying these shares. Take a look at the chart.

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JOY data by YCharts

Pick any time frame in the last five years and you'll have a hard time finding a period where the stock, which is down more 23% in five years, has made money for shareholders. During that span, both the Dow Jones Industrial Average (DJI)  and the S&P 500 have climbed some 77% and 93%, respectively.

It would seem the only ones making money on Joy Global are the short sellers who continue to bet against the company's improvements. As of the most recent settlement date, short interest on JOY now stands at 13,220,281 shares, up 6.4% since the start of the year.

This means almost 14% of JOY's 97 million outstanding shares are in the hands of those betting on the company to fail. And with earnings for the just-ended quarter projected to decline 25% to 57 cents per share, I'm not wagering my own money that things will change anytime soon. Not to mention, projected revenue for the just-ended quarter of $809 million would be a 13% decline from last year.

And if you're thinking of playing Joy with an eye toward fiscal 2016, think twice. In the past three months, analysts' average  earnings estimate for 2016 has dropped 21% from $3.68 per share to $2.90. This explains why short sellers continue to pile on. Pessimism about joy been a profitable gamble. In this case, the only ones who should "try, try again" are the shorts. 

This article is commentary by an independent contributor. At the time of publication, the author held no positions in the stocks mentioned.