Last year, this year, and in some of the years ahead 80% of my principle residence mortgage interest will not be allowed because of phase out of my itemized deductions. I am now shopping for a new home. It seems to me it may be wiser pay cash for house and then incur margin debt to buy securities the cash would have been used for. Given that I have enough interest and dividend income to write off margin interest, I understand this deduction is not subject to phase-out. Does anyone have any thoughts or experience in a situation like this?