The IRS Notice of Deficiency: The 90-Day Petition Deadline and What It Preserves

A statutory notice of deficiency—often called a 90-day letter—states that the IRS has determined an income, estate, gift, or certain excise-tax deficiency and gives the taxpayer an opportunity to petition the U.S. Tax Court before the IRS assesses and collects that deficiency. The notice should be treated as a court deadline, not as an ordinary request for documents.

The Petition Period

A petition generally must be filed within 90 days after the notice is mailed. The period generally is 150 days when the notice is addressed to a person outside the United States. The last date to petition is usually printed on the notice. If the final day falls on a Saturday, Sunday, or legal holiday in the District of Columbia, the deadline generally moves to the next business day. Timely-mailing rules may apply, but electronic filing through the Tax Court system avoids many mailing risks.

The IRS Generally Cannot Extend the Deadline

Continuing to communicate with the examiner, sending additional records, requesting Appeals review, filing an amended return, or asking the IRS to reconsider the adjustment generally does not extend the petition period. Under current law, the Tax Court generally lacks jurisdiction over an untimely deficiency petition. The taxpayer should preserve the deadline even when settlement discussions continue.

What a Timely Petition Does

A timely petition generally prevents assessment and collection of the deficiency while the case is pending and until the statutory post-decision period ends, subject to exceptions. The taxpayer usually may challenge the deficiency without first paying it. Many cases are resolved through IRS Counsel and Appeals without trial, but filing a petition begins litigation and requires compliance with Tax Court rules and orders.

If the Deadline Is Missed

After the petition period expires, the IRS generally may assess the deficiency and begin collection after required notices. Depending on the facts, the taxpayer may pursue audit reconsideration, pay and file a refund claim, seek Collection Due Process review of collection alternatives or eligible liability issues, or use another administrative procedure. Those routes are not equivalent to prepayment Tax Court review and have their own limitations and deadlines.

Verify the Notice and Address Issues

Review the notice date, last date to petition, taxpayer name, tax period, mailing address, certified-mail information, proposed tax and penalties, and prior administrative history. Whether a notice was validly mailed to the taxpayer's last known address can be legally significant, but a taxpayer should not assume an address defect will eliminate the deadline without a careful factual and legal review.

This article provides general federal tax information. A notice of deficiency is deadline-sensitive, and the actual notice and mailing history should be reviewed promptly.