The Rule of 72 Do you know how long it may take for your investments to double in value? The Rule of 72 is a quick way to figure it out. Share | Related Content Investments You’ve made investments your whole life. Work with us to help make the most of them. What’s Your Investment IQ? You make decisions for your portfolio, but how much do you really know about the products you buy? Try this quiz Keys to Investing for Retirement There are some key concepts to understand when investing for retirement.