NYS Tax Department: Governor's message regarding prepayment of 2018 real property tax

[Y2KEA]

Governor Andrew M. Cuomo has signed an emergency Executive Order that will allow New Yorkers to prepay next year’s property taxes this year, before the new tax law takes effect. Payments must be postmarked by December 31, 2017. For more information, contact the tax collector for each client's county.

The order authorizes localities to issue warrants for the collection of early property tax payments and to accept partial payment—allowing New Yorkers to pay a portion or all of their 2018 property taxes before the end of the year to keep the deductibility.

Check with each client's tax receiver to see if your clients are eligible to make an early payment. The deadline is December 31, so you must act quickly.

Payments made by mail and postmarked on or before December 31, 2017, will be considered timely. If their county accepts online payments, your clients may pay online until 11:59 p.m., Sunday, December 31, 2017.

For more information, see Executive Order #172.

[Uncle Sam]

Be careful.

Every municipal government is different in the way they accept the tax money - different year ends (fiscal vs calendar), different arrangements with credit card companies regarding collection of money (I checked around my local area and found that agreements are in effect not to credit card taxes until January), some will hold the money this week, cash it next week, etc.
So be sure that clients are prepared to do what's necessary to get the documentation in hand of prepayment so IRS can't question timing between payment date and banking date.

[Y2KEA]

Be careful.

Every municipal government is different in the way they accept the tax money - different year ends (fiscal vs calendar), different arrangements with credit card companies regarding collection of money (I checked around my local area and found that agreements are in effect not to credit card taxes until January), some will hold the money this week, cash it next week, etc.
So be sure that clients are prepared to do what's necessary to get the documentation in hand of prepayment so IRS can't question timing between payment date and banking date.

I don't currently do NY taxes but got this email from NY. Just posting what NY Cuomo.gov said. Buyer beware!!
And thanks for your input US.