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 Inflation and Your Portfolio Even low inflation rates can pose a threat to investment returns. The Investment Risk No One’s Ever Heard Of You face a risk for which the market does not compensate you, that can not be easily reduced through diversification. 5 Smart Investing Strategies Getting what you want out of your money may require the right game plan.