Dhe stock market shows an astonishingly stable pattern over long periods of time: Over the decades, savers can calculate with price increases and consequently with gains in value within a certain range. The stock markets of all major economies have continuously generated a return of between seven and twelve percent per year before inflation for the past 100 years. What power lies in these simple numbers and what wealth accumulation makes this possible in the long term cannot be demonstrated as elegantly with anything as with the 72 formula. With it, everyone can estimate for themselves how long it will take until their assets have doubled at a certain rate of return. This rule of thumb is commonly called the Reichmacher formula.