My questions are:
Should you have filed a return for 2017? One thing you could do is to print out the forms from the NY website and calculate them by hand to be sure you would have no NY tax liability for purposes of requesting NY Dept of Tax to waive the underpayment penalty they have calculated based on 90% of the "current year tax liability" for 2018.
By doing this, you are eliminating any possible "footholds" that NY might have for still assessing you the underpayment penalty.
As long as you should not have filed a 2017 return (because you did not), and
As long as you should not have had withholding taken out at the closing of the sale of your home and did not, then
Your best bet is to request they waive the underpayment penalty.
In general, you may owe the penalty for 2018 if you did not pay at least the smaller of:
• 90% (66⅔% for farmers and fishermen) of the amount of tax shown on your 2018 return; or
• 100% of the tax shown on the 2017 return (110% of that amount if you are not a farmer or a fisherman and the New York adjusted gross income (or net earnings from self-employment allocated to the Metropolitan Commuter Transportation District (MCTD)) shown on that return is more than $150,000 ($75,000 if married filing separately for 2018)). You must have filed a return for 2017 and it must have been for a full 12-month year; or
• 90% of the tax computed by annualizing the taxable income received for the months ending before the due date of the installment. Use Part 1 to see if you prepaid enough of your required annual tax payment. If you did not, use Part 2 or Part 3 to compute the penalty. If you checked filing status on your New York State return, each spouse must compute the penalty on separate Form(s) IT‑2105.9.
Another option you have is to do this:
If you are requesting a waiver of the penalty, submit a statement with Form IT-2105.9 containing all the facts necessary to justify your request.
-You didn't have a 2017 tax liability and were below the filing requirements (if you were) for 2017
-therefore, with a 2017 $0 tax liability, the withholding you had taken out met the exception requirements to waive the 2018 underpayment penalty.
-Request to please waive the underpayment penalty assessment due to the qualified exceptions
Exceptions to the penalty are at the following link:
IT2105.9 Instructions for 2018 NY underpayment penalty
