If you have equity in a property, you can release it by remortgaging and use it as deposits for further properties. For example, a property purchased for £100k with an £85k mortgage which is now worth £160k, could be remortgaged to 85% of its current value, releasing £51k in cash. Splitting this into two deposits and arranging new 85% mortgages, you can buy two more properties of the same value, TRIPLING the size of your portfolio. This concept applies no matter what size your existing portfolio. This could also triple their risk of losing money and that increasing borrowing should not be undertaken lightly.