From Sept. 1, 2011, to June 5, 2015, I managed Tier 1 Investments, a Motley Fool real-money portfolio that outperformed the market by more than 40% from inception to close. Within Tier 1, I sought out companies with the strongest competitive advantages, largest growth opportunities, and best management. I call these businesses Tier 1 enterprises, and no company fits that description better today than Amazon.com (NASDAQ: AMZN).