Veteran Motley Fool Hidden Gems members know what we love to find in a small company. Honest, competent management. Solid financials. High levels of insider ownership. Strong returns on equity and assets. Little or no Wall Street coverage. And a price that's right for long-term buyers.

But we don't often talk about the things that can go bump in the night -- the traits of bad small businesses that make us fear and loathe them.

There are more than 3,500 public companies capitalized at less than $500 million. And sure, there are loads of great winners in that bunch, poised to rise many times in value. Look back and you'll find companies such as Freeport-McMoRan Copper & Gold (NYSE: FCX), which has climbed nearly eight times in value in just the past seven years, turning a $5,000 investment into nearly $40,000.

These easy-to-understand businesses are the type that investing master Peter Lynch loved to own.

But let's not kid ourselves. Out of those 3,500 companies, there are tons of mediocre, and worse, companies. Like Tolkien's terrible dragon, Smaug, they can incinerate your savings in no time. (Hey, we said this was scary stuff!)

Quite seriously, if you're not doing business research and you don't know what to avoid, you could lose your fortune. When even seemingly solid companies such as Qualcomm (Nasdaq: QCOM) and St. Jude Medical (NYSE: STJ) can drop precipitously from their highs (each dipped more than 35% in 2006), you have to keep your eyes wide open.

Let's start with an example of what to avoid.

Case study: Charter Communications
In our active online community, a Hidden Gems member asked us a few years ago what we thought of Charter Communications, a broadband cable company whose chairman and largest shareholder is Microsoft co-founder Paul Allen. The business is also substantially owned by Wally Weitz, a Nebraska-based investor admired by Warren Buffett fans; Weitz found great returns in stocks like UnitedHealth Group and WellPoint (NYSE: WLP).

Charter stock had fallen from $25 to $4.50, and our member wanted to know whether it was a good time to get in for a turnaround.

In Hidden Gems, we absolutely love the broken small cap that's poised for a turnaround. Show us a company whose stock has fallen 90% from its highs, whose chairman is a billionaire, and whose largest institutional owner is a close friend of Warren Buffett, and we'll sign up to do very careful research. That's exactly what we did with Charter Communications at $4.50.

But we did not like what we found. Here's why we warned against investing in this business:

  • Massive debt. Net debt (debt minus cash) was more than $18 billion.
  • Net debt was 28 times the company's market cap of $640 million.
  • Charter was unprofitable, with $1.5 billion in yearly interest costs.
  • Debt covenants posed a serious threat to the company's survival.
  • The SEC had launched an investigation into Charter's accounting practices.
  • Heavy spending for cable infrastructure hadn't yielded high enough returns.

Near the end of June 2003, I (Tom) wrote negatively about this stock when it was trading at more than $4. It's tough to go contrary to Paul Allen and Wally Weitz. But there was no turnaround in sight, and the company's balance sheet was cratering. Charter itself soon crashed, dropping to less than $1 per share. The stock has been on a roller coaster since then, and it now sits around $0.95.

What we do and don't fear
Oddly enough, our Hidden Gems team does not fear high debt in and of itself. Our recommendation Middleby carried more than $100 million in debt after buying a competitor and repurchasing founder shares. Yet the stock has risen more than 580% since our original recommendation, and we remain very optimistic about its future. The company's operations are plenty strong to repay those obligations.

Nor do we fear companies that have fallen far from their all-time highs. Oilfield services company Baker Hughes (NYSE: BHI), for instance, climbed more than 400% after being knocked down hard in the late '90s.

Each of these scary factors individually could make for a compelling investment as the stock price drops into the real value range.

So what was the problem with Charter Communications? The answer is the scale of its debt, running north of $18 billion, alongside harsh payment terms and emerging accounting problems.

To find out which stocks we do love, simply take a free trial to Hidden Gems. Read about all the many small companies that have thus far produced outsized returns. If you don't like it, you can cancel within 30 days without paying a dime.

This article was originally published on Jan. 13, 2005. It has been updated.

Tom Gardner and Rex Moore anchor the gold-medal-winning Motley Fool 4x100 three-legged sack race relay team. Tom owns shares of Microsoft; Rex owns shares of Microsoft and Qualcomm. UnitedHealth is an Inside Value and Stock Advisor recommendation. Microsoft is also an Inside Value pick. The Motley Fool has a disclosure policy.