Mortgage interest tax deductibility is needed to treat debt and equity financing of homes equally. Countries that limit deductibility create a debt tax penalty that presumably leads households to shift from debt toward equity financing. The greater the shift, the less is the tax revenue raised...

During the last quarter century, mortgage interest deductibility has been gradually phased out. In 1974 a ceiling was set on the size of the mortgage eligible for interest deductibility (œ30,000 since 1983) and, beginning in 1993, the maximum rate at which interest under that ceiling could be...