Fraser, you fail to see the point. The aim is not to increase the supply of "rental houses" for renters. The aim is to decrease the amount of people that need to rent because it sucks and instead to give those people the opportunity to own their own home. The only way to do that is to have more homes built and/or get those wonderful entrepreneurs to sell. I'm sure if they're as entrepreneurial as you claim, they can find other ways to risk their capital. And if albo owns 5 houses, great, he can pay the tax too. But in future, people might think twice about accumulating multiple houses at the expense of others. By renting out houses, you are in fact depriving someone else from owning their own home and subjecting them to a miserable/less powerful life of renting where they are at the beck and call of unscrupulous property agents and can be forced to move at any time. But you're OK with that because you're getting richer because of the genius and the sheer courage that you possess to invest! Bravo!