There is a significant change in interest deductibility in this bill, introduced by way of a Supplementary Order Paper (SOP), and the change is significant because it really does show a change from previous practice. I wish to direct the attention of the House towards section DA 1 of the Income Tax Act. It is the "General permission". And what it says is that a person is allowed a deduction for an amount of expenditure—so you can get a deduction for your interest expenditure—to the extent to which the expenditure is incurred in deriving assessable income. Or, if you're doing it through a business, it's incurred in the course of carrying on a business, creating assessable income. Here's the thing when it comes to interest costs on housing: a great part of what is earned through housing, through owning houses, is not assessable income; it's a capital gain. And, in the tax law in New Zealand, capital gains, for the large part, are simply not assessed. They're not regarded as assessable income. It's a tax-free capital gain. Why, then, should you get an interest deduction for income which is not part of the tax base? It's not incurred in deriving assessable income. Why get the interest deduction?