Rainy, check if your mortgage has a redraw facility OR a 100% offset account that you can bank it into (and if so how much it costs to redraw). The interest saved on 100K over 2 years would be a huge savings AND unlike other investments you don't have to pay tax on the benefit to you. Just make sure that the mortgage account stays open if you reach a zero balance during that 2 years. You wouldn't want the account to close and gobble up the 100 K!