payment

[busdrvr]

I owe $9***n in tax this year.  Again because of a stock sale/capital gains event.  That is clearly over the $1000 lower limit that is suggested to generate an "underpayment penalty"    Since I did not know/foresee in 2019 that I would be selling stock and owing capital gains in 2020, subsequently not paying estimated tax for 2020,   

     Will I be charged an underpayment penalty?

Is there any way to avoid an underpayment penalty?

[SweetieJean]

Probably not, as you could have made an estimated tax payment when you actually sold the stock, or shortly thereafter.  But some long term capital gains are taxes at 0% for Federal, depending upon your overall income.  State taxes may be different, though.

Capital Gains Tax Rates: Here’s What You Need To Know for Tax Year 2020 (msn.com)

[DavidD66]

Generally, if you owe less than $1,000, you do not have to pay quarterly estimated tax payments and will not see an estimated tax penalty. If you pay at least 90% of your tax obligation or 100% of the tax owed in the prior year (whichever is smaller), then penalty can be avoided. If you are a high-income taxpayer, with an AGI over $150,000, then the 100% is increased to 110%.

For more information, see the following TurboTax article:

Estimated Tax Penalty Explained (How to Avoid Penalty)