I was traveling to US two weeks back when i read a weekend article on the Business Times on the “risk of cash”.  The simple concept is presented in the chart below.  How to double the money you have now ? Assume you have $100,000 now and you invest in a portfolio that gives you an annualised return of 7.2%. In 10 years time, you will have $200,000.  However, if you decide to invest only 20% of the cash and keep 80% of the cash for rainy days, then you will need that portfolio to make an annualised return of 18.76% before you can double your money in 10 years. As you are well aware, an annualised return of 18% is highly unlikely.  If you want to keep 50% in cash and invest the 50%, then an annualised return of 10% is needed. Furthermore, the chart below shows you