The state of IL sent me a letter claiming i owe $209 of late payment. However, i filed my taxes in February. Why does IL say i didnt make full estimated payment?

[frankavino13-gma]

Filed through Turbotax; filing year 2023; late estimated payment penalty is $209, but i have no unpaid taxes.

[TomD8]

Do you make quarterly estimated tax payments?

Illinois estimated payments are due on the 15th day of the 4th, 6th, 9th, and 12th months of the tax year.

https://tax.illinois.gov/businesses/business-income-tax-estimated-payments.html#:~:text=Estimated%20....

Even if your taxes were paid in full, you could still be assessed a penalty if any of your estimated payments were made late.

[Opus 17]

Income taxes are pay as you go.  If you don't have enough withheld during the year (or make sufficient estimated payments) so that you owe more than $1000 when you file, you can be assessed a penalty for underpayment throughout the year, even if you pay in full when you file.  See this for more,

https://tax.illinois.gov/research/publications/pubs/illinois-estimated-payments-requirements-for-ind...

If you did not owe more than $1000, the letter may have been sent in error.  Write to the office that sent the notice with your explanation and copies of any relevant documents.