Must I pay quarterly estimate the year after one time capital gain

[AmyC]

No. You should just make sure that you pay the IRS whenever you make money. The IRS expects payment the same quarter you earn it. You can make a payment anytime you have a windfall at Payments.

You must not have made a payment when you should have so now you owe money and the program is trying to help out. As long as you owe less than $1,000 at tax time, the IRS is happy. If you owe more than  $5,000 it is considered a substantial underpayment with penalties and interest and you do not want to continue that trend.