5 Smart Investing Principles The slideshow presentation that you would like to view is too large for your current screen resolution. Click here to view to view the slideshow at full resolution. Launch Presentation » Share | Related Content 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. The Anatomy of an Index The S&P 500 represents a large portion of the value of the U.S. equity market, it may be worth understanding. Keys to Investing for Retirement There are some key concepts to understand when investing for retirement.