<prompt> Human: Well, the house and senate tax plans both limit property tax deductibility to 10k per year starting in 2018. Is your annual property tax bill more than 10k? Then there may be a one-time opportunity depending on your situation: 1 check with your taxing municipality to ensure they allow prepayments. Mine will allow prepayment from Dec 1-Dec 29, up to the amount paid the prior tax year. 2 check with your accountant or your tax software to ensure that an additional X of property tax paid wont turn you into an AMT payer in 2017. 3 pay the portion of your tax bill that is greater than 10k. Mine is 19k, so ill Prepay 9k, and pay the remaining 10k in 2018. In effect, this strategy allows you to gain deductibility on the full property tax bill one last time. In my example, this will have a cash benefit of 9,000marginal tax rate - 2-4k depending on your income. Certainly greater than the 6 months of interest I would have earned on that 9,000.As always, check with your accountant before you take action based on a stranger on the internet. Just giving you a heads up to look into this one time tactic.  <response>: Another possible tactic. Prepay your January 1st mortgage payment in December. That way you can count that mortgage interest towards 2017. No prepayment for any other month in 2018 is allowed by the IRS. But apparently, the January 1st payment is allowed early because that payment applies to December 2017. 