David Tepper scooped up over 7 million shares of Lyft stock last quarter. Whenever I'm looking for a new investment opportunity, one thing that I enjoy doing is looking at 13F filings from hedge funds. These documents break down the stocks that high-profile investors bought and sold during a given quarter. David Tepper of Appaloosa Management is one investor I like to keep an eye on. Last quarter, he bought 7.5 million shares of ride-hailing app Lyft (LYFT 2.25%), increasing his position by 1,600%. Let's di ...