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. Related Content Impact of Taxes and Inflation Estimate the potential impact taxes and inflation can have on the purchasing power of an investment. A Taxing Story: Capital Gains and Losses Understanding how capital gains are taxed may help you refine your investment strategies. Split Annuity Strategy Here's one strategy that combines two different annuities to generate income and rebuild principal.