Specific Types of Representation · Representing a taxpayer before Appeals
Issuance of the 90-day letter
tax year · reviewed 2026-08-19 · I. Ohu
The rule
The notice of deficiency is the document that gives the United States Tax Court jurisdiction. It is authorised by IRC § 6212(a): where the Secretary determines a deficiency in a tax imposed by subtitle A or B or chapter 41, 42, 43 or 44, the Secretary may send notice of it to the taxpayer by certified or registered mail. The statute also requires the notice to tell the taxpayer of the right to contact a local office of the Taxpayer Advocate, with that office’s location and phone number.
What follows is the reason practitioners call it the ticket to the Tax Court. IRC § 6213(a) gives the taxpayer 90 days after the notice is mailed — or 150 days if the notice is addressed to a person outside the United States — to file a petition with the Tax Court for a redetermination of the deficiency. Saturdays, Sundays and legal holidays in the District of Columbia do not count as the last day. During that period, and while a filed petition is pending until the Tax Court’s decision becomes final, no assessment of the deficiency and no levy or court proceeding for its collection may be made, begun or prosecuted, except under the jeopardy and termination provisions of §§ 6851, 6852 and 6861.
The prohibition has teeth. Notwithstanding the Anti-Injunction Act at IRC § 7421(a), an assessment or levy made while the prohibition is in force may be enjoined, including by the Tax Court, and a court may order a refund of anything collected during the prohibited period — though the Tax Court has that power only where a timely petition for redetermination has been filed.
Mailing to the last known address is sufficient. Under § 6212(b)(1), in the absence of notice of a fiduciary relationship under § 6903, a notice mailed to the taxpayer at the last known address is sufficient even if the taxpayer is deceased, is under a legal disability, or, being a corporation, has terminated its existence. A joint return may take a single joint notice, except that where the Secretary has been notified that separate residences have been established, a duplicate original must go to each spouse by certified or registered mail.
The notice can be rescinded, but only with consent. Section 6212(d) permits the Secretary, with the taxpayer’s consent, to rescind a notice of deficiency. A rescinded notice is not treated as a notice of deficiency for the further-deficiency-letter restriction, for the § 6213(a) petition right, or for § 6512(a) — and the taxpayer has no right to petition on it. Critically, rescission does not undo the suspension of the limitations period that ran while the notice was outstanding.
Current figures
| Item | Period or amount |
|---|---|
| Period to petition the Tax Court | 90 days after the notice of deficiency is mailed, or 150 days if addressed to a person outside the United States, not counting a Saturday, Sunday or District of Columbia legal holiday as the last dayTY2026 |
| Tax Court small case procedure — deficiency cases | $50,000 for any one taxable year for taxes imposed by subtitle A; $50,000 for the chapter 11 estate tax; $50,000 for any one calendar year for the chapter 12 gift taxTY2026 |
| Tax Court small case procedure — other petitions | $50,000 of relief sought under IRC § 6015(e), $50,000 of unpaid tax on a § 6330(d)(1)(A) collection due process appeal, or $50,000 of abatement sought under § 6404(h)TY2026 |
The small case procedure is elected by the taxpayer with the Tax Court’s concurrence before the hearing. A decision entered in a small case is not reviewable in any other court and is not treated as precedent for any other case (IRC § 7463(b)).
How it works in practice
The 90 days cannot be extended. This is the single most consequential fact on the page. It is a statutory jurisdictional period, not an administrative deadline, and no IRS employee has authority to give more time. A representative who telephones to ask for an extension because documents are still being gathered will be told, correctly, that none is available. The only things that change the arithmetic are the 150-day period for a notice addressed to a person outside the United States, and the exclusion of a Saturday, Sunday or District of Columbia legal holiday as the last day.
The choice at day one is a fork, not a sequence. Petitioning the Tax Court preserves the prepayment forum: the deficiency cannot be assessed or collected while the case is pending. Declining to petition means the deficiency is assessed, and the remaining route is to pay, file a claim for refund, and sue in a district court or the Court of Federal Claims. Both are real options, and clients with a strong record and no ability to pay usually belong in the Tax Court. What is not an option is to let the period lapse while negotiating with Appeals, which is how the right is most often lost.
Appeals and the notice can overlap. Many cases reach Appeals before a notice issues, on a thirty-day letter and a protest. A notice may also issue while Appeals holds the file, most often because the assessment statute is running out. A case in which a notice has issued is a docketed case once a petition is filed, and Appeals may still settle it. The existence of a live Appeals discussion does not toll the 90 days, and a representative who treats it as though it does has mistaken a courtesy for a rule.
Not every IRS letter is a notice of deficiency. A math or clerical error notice under § 6213(b)(1) is expressly not a notice of deficiency: the taxpayer has no right to petition the Tax Court on it, the assessment is not prohibited, and the notice must set forth the error alleged and an explanation of it. The taxpayer’s remedy there is a request for abatement within the statutory window, which then forces the Service into deficiency procedures if it wants to persist.
The statute of limitations stops while the notice is outstanding. Issuing a notice suspends the running of the assessment period under IRC § 6503(a) — which is why notices are often issued against a closing statute rather than at the natural end of an examination, and why a client may receive one abruptly after months of quiet.
Ninety days spent negotiating
Aurelio Sandström receives a notice of deficiency and immediately opens a productive conversation with an Appeals officer who has the file. Documents go back and forth; the officer is constructive. On day 96 the officer says the case cannot be settled after all.
The petition period has expired and nothing can restore it. The right course was to file a protective petition inside the 90 days and continue negotiating with the case docketed — Appeals can and does settle docketed cases, and filing costs a modest fee and does not end the discussion. The error was treating a cooperative negotiation as a reason to let a jurisdictional clock run. No IRS employee has authority to extend it, and none purported to; Sandström simply assumed.
The notice that went to an old address
Ndidi Falkenrath moved two years ago. She filed returns from the new address but the notice was mailed to the old one and forwarded too late. She learns of it on day 103.
The question is whether the notice went to her last known address. If it did, the notice is sufficient under § 6212(b)(1) whatever happened to the mail, and the petition period ran from mailing. If it did not — and returns filed from a new address are the ordinary way the Service learns of one — then the notice may be invalid, in which case there is no assessment and the Service must issue a valid one. The representative’s first act is to obtain the notice, the certified mail record and the account transcript, and to establish what address the Service held and when. This is one of the few situations where a late-discovered notice is not the end.
Choosing the small case procedure
Ptolemy Achterberg has a deficiency of about 28,000 dollars for one year, arising from substantiation of business expenses. He has records but no lawyer and cannot afford one.
The small case procedure fits: the deficiency for the single taxable year is under the statutory ceiling, the proceedings run under relaxed rules of evidence and procedure that the Tax Court prescribes, and Achterberg can present his own records. The trade is stated in the statute: the decision is not reviewable in any other court and is not precedent for any other case. For a substantiation dispute that trade is easy, because there is no legal question worth appealing. For a case turning on a contested reading of a statute it is the wrong election, and the representative should say so — the ceiling makes the procedure available, it does not make it advisable.
How this has changed
The 90-day letter has been the architecture of deficiency procedure since the Revenue Act of 1924 created the Board of Tax Appeals, and the core of § 6213(a) has changed little. The additions that matter are recent and procedural. Section 6212(d), the consensual rescission authority, was added in 1988. The requirement that a notice state the Taxpayer Advocate’s local office, location and phone number came with the taxpayer rights legislation of the 1990s. The Tax Court small case ceiling has been raised over time and now stands at the figure in the table.
The most significant modern development is not in § 6212 or § 6213 at all: it is the Taxpayer First Act’s creation of a statutory right to an independent appeal at IRC § 7803(e), together with § 7803(e)(5), which constrains the Commissioner’s ability to deny referral to Appeals to a taxpayer who is in receipt of a notice of deficiency and requests it. Before 2019, a taxpayer holding a 90-day letter who had never been to Appeals had no statutory recourse if referral was refused; now the refusal must come with detailed written reasons and a protest procedure, unless the position is frivolous.
Exam focus
Know the two periods and which is which: 90 days ordinarily, 150 days where the notice is addressed to a person outside the United States, and remember that a question asking for the maximum wants 150. Know that the period cannot be extended by the IRS and that no assessment or levy may occur while it runs. Know the Tax Court small case ceiling and that it applies per taxable year in a deficiency case, and that a small case decision is final, unappealable and not precedent. A question may also test that a math error notice is not a notice of deficiency.
Check yourself
1. What is the maximum period in which a taxpayer may petition the Tax Court after a notice of deficiency is mailed?
A. 30 days B. 60 days C. 90 days D. 150 days
Answer: D. The ordinary period is 90 days; it is 150 days where the notice is addressed to a person outside the United States, so the maximum is 150.
2. What is the maximum amount of deficiency for any one taxable year for a case to qualify for the Tax Court small case procedure?
A. 20,000 dollars B. 30,000 dollars C. 50,000 dollars D. 100,000 dollars
Answer: C. The ceiling applies to the amount of the deficiency placed in dispute, or any claimed overpayment, for any one taxable year.
3. While the petition period runs and before any petition is filed, what may the IRS do?
A. Assess the deficiency but not levy B. Neither assess the deficiency nor levy or sue to collect it C. Levy on wages but not on bank accounts D. Assess and collect freely, since no petition has been filed
Answer: B. Assessment, levy and collection proceedings are all prohibited until the period expires, and until any Tax Court decision becomes final if a petition is filed — jeopardy and termination assessments aside.
4. A taxpayer receives a notice stating that a mathematical error on the return produced additional tax, which has been assessed. May the taxpayer petition the Tax Court on that notice?
A. Yes, within 90 days of mailing B. No; such a notice is expressly not a notice of deficiency for that purpose C. Yes, but only if the amount exceeds the small case ceiling D. Only after paying the additional tax
Answer: B. The remedy is a request for abatement within the statutory window, which pushes the Service into deficiency procedures.
5. A taxpayer consents to rescission of a notice of deficiency. What is the effect on the assessment limitations period?
A. The suspension that ran while the notice was outstanding is undone B. The period is suspended for a further 90 days C. The suspension that ran while the rescinded notice was outstanding is unaffected D. The period expires immediately on rescission
Answer: C. Rescission removes the petition right and the further-deficiency-letter restriction, but expressly does not affect any suspension that already ran.
Change log
- Initial draft.