Good afternoon,
I know to qualify for safe harbor law to not receive and underpayment you have to cover 110% (we gross over 200,000) of your previous years owed tax filings.
My questions is:
Now we are divorce so I will be filling single. Is safe harbor calculated as 110% of the whole amount of taxes owed together from the previous year, or is it calculated just using my portion of the owed taxes from the previous year?
The situation does not seem to be specifically described in either the relevant law or treasury regulations, other than frequent use of the word "individual." Without some other expert to contradict me, I would say the payments need to be 110% of what your tax payments would have been if you were filing single in the previous year (not just half your married tax payments, but equal to what you would have owed if filing single.)
This does not seem like an easy thing for the IRS to calculate, so if you are on the edge, you might want to overpay, or you might have to file an appeal later if they assess a penalty based on your not paying 110% of your married taxes.
Page 4 of the Instructions for Form 2210 addresses this. You'll use your respective share of the 2023 tax liability shown on the joint return.
https://www.irs.gov/pub/irs-pdf/i2210.pdf