I'm being told I may owe an underpayment penalty for 1026 Michigan State Tax. I paid EXACTLY the amount TurboTax told me to pay last year. I could I have underpaid?

[BMcCalpin]

The underpayment penalty is not assessed on what you pay with your tax return, it is assessed on whether you paid enough each quarter and at the end of the tax year.

Generally, by the end of the year, you should have paid either by withholding or estimated tax payments one of the three following:

• 90 percent of the tax shown on your 2016 tax return, or
• 100 percent of the tax shown on your 2015 tax return, or
• 110 percent of the tax shown on your 2015 return if 2015 Adjusted Gross Income (AGI) was more than $150,000 if filing joint or single ($75,000 if your 2016 filing status is married filing separately).
  

That is, the State (just like the federal government) wants its money during the year, not all at the end. Note that the underpayment penalty can also apply if you don't pay even during the year, corresponding to your income.

The form that computes the underpayment penalty is M-2210.

[Redleg2]

Michigan wants me to pay a under payment penalty because I sold stock  December 24, 2020.  There must be something wrong here.