Earlier this year, the IRS provided additional expanded penalty relief (PDF) to individual taxpayers whose 2018 federal income tax withholding and estimated tax payments fell short of their total tax liability for the year.

https://www.irs.gov/forms-pubs/irs-automatically-waives-estimated-tax-penalty-for-eligible-2018-tax-filers-16-aug-2019

The IRS is now automatically waiving the estimated tax penalty for eligible taxpayers who already have filed their 2018 federal income tax returns but who did not claim the waiver. Filing Form 843 for Expanded Underpayment of Estimated Income Tax Penalty Relief, posted March 27, 2019, is superseded to the extent it directs individual taxpayers who already have paid the penalty to file Form 843 to claim a refund.

Over the next few months, IRS is mailing notices (CP21) to affected taxpayers notifying them the penalty was waived. The automatic waiver has been granted to any eligible taxpayer whether or not they already have requested penalty relief on Form 843. After receiving their notice in the mail, taxpayers who already have paid the penalty should receive their refunds within three weeks, if they don’t owe any other taxes or debt the IRS is required to collect. Eligible taxpayers who already have filed a 2018 return do not need to request penalty relief, contact the IRS, or take any other action to get this relief.

The automatic waiver applies to any individual taxpayer who paid at least 80 percent of their total tax liability through federal income tax withholding or quarterly estimated tax payments but did not claim the special waiver available to them when they filed their 2018 return earlier this year. This waiver is designed to provide relief to any taxpayer who filed too early to take advantage of the waiver or was unaware of it when they filed.

For those yet to file, the IRS urges every eligible taxpayer to claim the waiver on their return. This includes those with tax-filing extensions due to run out on October 15, 2019. The fastest and easiest way to do that is to file electronically and take advantage of the waiver computation built into their tax software package. Those who choose to file on paper can fill out Form 2210 (PDF) and attach it to their 2018 return. See the Instructions for Form 2210 for details.

If you have questions about the notice or it’s been longer than three weeks, you may call the toll-free number listed on the top right corner of the letter.