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 | Have A Question About This Topic? Name Email Address Message Thank you! Oops! Related Content Behavioral Finance An amusing and whimsical look at behavioral finance best practices for investors. Required Reading: The Economic Report of the President The Economic Report of the President can help identify the forces driving — or dragging — the economy. 5 Smart Investing Principles Principles that can help create a portfolio designed to pursue investment goals.