With an average dividend yield of about 9.8% at recent prices, even a small investment in these stocks could significantly boost your passive income stream. If you're an investor who doesn't already have access to billions in capital, you could probably learn a few things from the folks who do. Luckily, keeping tabs on the world's most successful investors isn't very hard to do. Every three months, people managing a portfolio worth $100 million or more have to report their trading activity to the Securities ...