Co-founders Tom and David Gardner look back on The Motley Fool's journey with (NASDAQ:AMZN) since first purchasing it in September 1997. The brothers discuss the ups and downs they've seen with the stock, now a 100-bagger for the Fool.

Investing in the businesses he loves, not playing the stock market, is the key to David Gardner's approach to investing and his market-beating success -- a success he shares with The Motley Fool through services such as Rule Breakers, Stock Advisor, and more.

Tom Gardner: You're the best investor at our company. What does it feel like, to you, to have a 100-bagger investment in the portfolio, that you know members are buying and talking about? What is motivating you as an investor when you're looking for the companies that you're finding?

David Gardner: Well, this is the last thing I'll say for now. Basically, Tom, for me the purpose of our company is to help the world invest better and what I think about all the time is the people who are buying with us.

You're taking a risk when you buy companies with very high price-earnings ratios or -- all of a sudden Barron's comes out with "Amazon.bomb" on the cover in the year 2000 or so.

But if you stay focused on the businesses -- us as investors, Tom, your service's incredibly accomplished work in great numbers, and across The Motley Fool. Heck, Inside Value was recognized by Hulbert Financial Digest as one of the top three performers in the last five years, so, The Motley Fool has an incredible efflorescence of market-beating services and advice.

I think what unites us all, more than anything, is that we're business-focused. That's the number one thing that I see running right through The Motley Fool. We are essentially MBAs without MBAs. We love business, and we're doing that. We're just becoming part-owners of businesses; we're not playing with stocks.

Tom: A 100-bagger. What an incredible achievement by you and the team in Rule BreakersStock AdvisorSupernova, and all the services you're running. I will just close with this point of emphasis -- although there are five or six or seven different great points here in this conversation.

Amazon, a 100-bagger, it took 16 years. That's just a reminder that that's how you get these multi-bagger, awesome returns. They happen over 5 or 10 or 15 or 16 years, and it can transform your portfolio. Dave, thanks for sitting down and talking a little Amazon, and best of luck finding the next 100-bagger. I can't wait to buy right along with you!

David: Thanks a lot, Tom. That was fun.

John Mackey, co-CEO of Whole Foods Market, is a member of The Motley Fool’s board of directors. David Gardner owns shares of Tom Gardner owns shares of Chipotle Mexican Grill and Whole Foods Market. The Motley Fool recommends Chipotle Mexican Grill, Costco Wholesale, and Whole Foods Market. The Motley Fool owns shares of Chipotle Mexican Grill, Costco Wholesale, and Whole Foods Market. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.