I've mentioned in this space before our eternal efforts to uncover small companies that will eventually appreciate many times in value. The legendary Peter Lynch called them "multibaggers," and they are the real difference makers in a lifetime of investing -- the ones that easily make up for mediocre and failed investments.

Just ask anyone who put $1,000 in Home Depot (NYSE:HD) in late 1984 and watched it turn into $138,000. Or how about those who saw the turnaround under way at women's clothier Chico's FAS (NYSE:CHS) in 1997 and turned $1,000 into more than $100,000? In Hidden Gems, we look for unknown or unloved companies -- and even those considered broken by most investors.

Today, I thought it would be interesting to look at Audible (NASDAQ:ADBL), and why it turned into a seven-bagger for me over a 14-month period. Perhaps we can learn why, in that short period of time, it achieved what it takes an index fund about two decades to reach at historical market growth. We love indexing and think it should be a core part of your portfolio, but Audible offers a great example of how small-cap investing can really juice your returns.

Hear me now
Audible is the No. 1 provider of spoken-word content on the Internet. Besides audio books, it also provides daily newspaper and magazine articles, interesting speeches, and various other nifty things. Users can download the content to listen via encoded MP3 files on their portable player, burn it onto a CD, or just listen on their computer.

In typical Lynchian fashion, I was a loyal Audible customer before I thought about the company as an investment. I commute to Fool HQ 30 minutes each way, and in 2000 I found that Audible's audio books not only made that time on the Capital Beltway fly by but also educated, amused, and enriched me in ways I would never have imagined.

When I started, a $14.99 monthly fee allowed me to download two books each month. I was able to catch up on things I should have read long ago but never had the time. The Hobbit motivated me to read the entire Lord of the Rings trilogy. Jeffrey DeMunn's narration of Stephen King's Dreamcatcher was outstanding. Ernest Hemingway's The Old Man and the Sea was short but sweet. Atlas Shrugged, Ayn Rand's 55-hour epic, was not short. I would never have discovered such gems as Ender's Game and Life of Pi if it weren't for Audible. All "told," nearly 100 books have passed through my now-ancient Rio 500 MP3 player and into my head.

Barely audible
When I looked at the company as an investment possibility, the stock was below $1 per share, down from the $45 range after its 1999 IPO. The business had never been profitable and was in danger of running out of money and closing its doors. It was too risky for me then, but I kept an eye on it. Over the months, things began to stabilize somewhat. Sales growth, after decelerating from 1999 through 2002, began accelerating again. The stock price doubled from its lows. There were still many obstacles to overcome, but -- because of the strength of the product, high inside ownership, and the dedication of Chairman and CEO Donald Katz -- I believed the company would get past the bad times and flourish.

In September of last year, I bought in at $1.14 per share. This was before I joined the Hidden Gems team, and, unbeknownst to me, Tom Gardner placed it on his Gems Watch List in the October 2003 issue, citing a move toward positive free cash flow, non-dilutive management, top-line growth, and other improving fundamentals.

Since then, we've seen four straight quarters of positive cash from operations, the first quarter of GAAP profitability, a reverse stock split (which raised my cost basis to $3.50 per share), a relisting on the Nasdaq, a deal with Apple (NASDAQ:AAPL) to get content in the iTunes Music Store and to make the hot-selling iPod players "Audible ready," and a stock price that has risen more than 600%.

Also, investors have come to realize the potential of Audible's distribution system. Netflix (NASDAQ:NFLX) CEO Reed Hastings has mentioned Audible as one of the small companies he most admires. I can't help but wonder how much more efficient and profitable his business would be if it didn't have to mail out all those DVDs. One day, when broadband becomes even broader and other technology is in place, Netflix and competitors Blockbuster (NYSE:BBI) and Wal-Mart (NYSE:WMT) will be able to distribute movies the same way Audible offers books. Perhaps Audible, with its first-mover expertise, will even have a hand in it all.

A Gem-dandy
My point here is not to extol the virtues of Audible. By all standard measures, it's now a very pricey stock and certainly out of Tom's buy-in range. It is no longer a value play. Don't get me wrong; I believe in the company's future and will continue to hold all or part of my position. Just understand that it's still a high-risk investment.

Instead, I think it's instructive to look back at some of the characteristics that made it a Hidden Gem in the first place:

  1. After a period of decline, accelerating sales growth
  2. High inside ownership
  3. Non-dilutive, shareholder-friendly, dedicated management
  4. Strong price appreciation potential based on Tom's valuation method
  5. Underfollowed and unloved

When we find companies like this at Hidden Gems, we become very interested and dig deeper, making sure that all the pieces of the puzzle fit together. And the results so far have been excellent. If you're interested in our approach and want to receive two stock recommendations each month, Tom is offering a special 30-day free trial.

Rex Moore has gone through four sets of earphones on his Rio 500. At the time of publication, he owned shares of Audible. The Fool has a disclosure policy.