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 The Business Cycle How will you weather the ups and downs of the business cycle? 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.