Read full story for latest details. : While some of their investing strategies that are obviously out of reach to most people — such as acquiring a controlling stake in a company — there are common billionaire investment techniques that anyone can use. Here are three that could amplify your returns. Even after tax reform, the highest personal tax bracket in the U.S. is 37%. On top of that, there's a 3.8% net investment income tax that applies to high earners. And depending on where you live, there may be state and local taxes as well.