Blog · 14 October 2026

Notice of Deficiency and the 90-Day Tax Court Petition After Lindsey: §6213(a), Mailing Proof and What US CPA Firms Should Tell Clients

By Keshav Bansal, CA

A notice of deficiency (often called a 90-day letter) is how the IRS opens the door to Tax Court. Under IRC §6213(a), the taxpayer generally has 90 days from the date the notice is mailed—or 150 days if addressed outside the United States—to file a petition. In Lindsey v. Commissioner, T.C. Memo. 2026-94 (filed September 24, 2026; Judge Jones), the Tax Court held that the IRS had proved mailing of the notice even though USPS Form 3877 was incomplete, dismissed the petition as untimely, and applied the Seventh Circuit’s rule that the §6213(a) deadline is jurisdictional with no equitable tolling. For US CPA firms, Lindsey is a calendar-and-mailing case: the petition clock starts on mailing to the last known address, not on actual receipt.

What happened in Lindsey

Per Ed Zollars’s analysis in Current Federal Tax Developments (September 24, 2026) of Lindsey v. Commissioner, T.C. Memo. 2026-94, Valarie Lindsey, an Illinois resident, timely filed Forms 1040 for 2017 and 2018 and claimed charitable deductions of $35,700 (2017) and $41,070 (2018). Exam began in 2019. On October 21, 2019, the IRS issued a 30-day letter (Letter 950) proposing full disallowance of those deductions, the standard deduction, and accuracy-related penalties under §6662(a).

Lindsey protested to Appeals. Appeals Officer Michele Penry in Indianapolis was assigned on February 14, 2020. COVID closures shut the Indianapolis office in March 2020; a notice of deficiency was prepared, and the case was released to Detroit APS on July 23, 2020. Tax Examiner LaTrese Lindsey prepared certified mail article No. 7017 0660 0001 1692 6930 to Lindsey’s last known address. An ACDS entry recorded the mailing on August 10, 2020 (ACDS entries cannot be backdated).

USPS Form 3877 was incomplete: no postmark, no USPS employee signature or initials, and no piece count. The IRS conceded that Form 3877 therefore did not create a presumption of mailing. USPS Product Tracking and Reporting (PTR) showed the article entered the mail stream in Pontiac, Michigan, on August 10, 2020; it was never delivered and was returned to an IRS Detroit FOIA P.O. Box on February 3, 2021. The Appeals Officer and Tax Examiner were not notified of the return.

The IRS assessed on June 14, 2021: deficiencies of $8,163 (2017) and $7,935 (2018), plus §6662(a) penalties of $1,633 and $1,587. Lindsey petitioned Tax Court on October 20, 2022—710 days after the petition deadline if the notice was mailed August 10, 2020. The 90-day window expired Monday, November 9, 2020 (the 90th day, November 8, was a Sunday).

Holding: mailing proved without a clean Form 3877

The Tax Court held that the IRS still proved mailing by otherwise sufficient circumstantial evidence—ACDS records, PTR data, habit testimony, and copies of the notice—despite the defective Form 3877. Actual receipt is not required when the IRS mails the notice to the taxpayer’s last known address under §6212. For CPA firms responding to exam or SFR work that later becomes a deficiency notice, see our guides to the IRS substitute for return after Jackson and IRS audit rates and CP2000 notices.

§6213(a), Golsen, and the circuit split on tolling

Under the Golsen rule, Tax Court follows the Court of Appeals to which the case is appealable. Lindsey lived in Illinois, so Seventh Circuit precedent controlled. In Tilden v. Commissioner, 846 F.3d 882 (7th Cir. 2017), the Seventh Circuit held that the §6213(a) petition deadline is jurisdictional; equitable tolling is unavailable. The Tax Court applied that rule and dismissed.

Per Current Federal Tax Developments and the Sullivan & Cromwell Tax Policy Update (September 29, 2026), circuits remain split on whether the deadline is jurisdictional:

• Jurisdictional (no equitable tolling): Seventh Circuit (Tilden); Ninth Circuit (Organic Cannabis; Seekamp 2026); Tax Court Hallmark/Sanders line outside the Third Circuit.
• Non-jurisdictional (tolling available or presumptively available): First Circuit (Kyick Holdings 2026—non-jurisdictional but tolling denied on the facts); Third Circuit (Culp); Second Circuit (Buller 2025); Sixth Circuit (Oquendo 2025); Eighth Circuit (Maniktala 2026).

Sullivan & Cromwell notes that Lewis v. Commissioner, No. 26-1173, asks the Seventh Circuit to overrule Tilden. Until that happens, Tilden still binds Illinois and other Seventh Circuit taxpayers. Do not tell clients that every circuit allows tolling.

What remains after a late petition

Per the opinion’s footnote 9 as summarized by Current Federal Tax Developments, post-dismissal remedies include paying in full under the Flora full-payment rule, filing a Form 1040-X refund claim under §§6511 and 7422, and then suing in District Court or the Court of Federal Claims under §6532. Collection Due Process later may also be available. When assessment has already stuck and the client needs payment plans, offers in compromise, or related collection framing, see our IRS collection alternatives guide.

What US CPA firms should tell clients

• Diary the mailing date, not the receipt date. Under §§6212 and 6213(a), mailing to the last known address starts the 90-day (or 150-day) clock. “I never got it” does not restart Tax Court jurisdiction.
• Keep the last known address current. A certified-mail piece that returns undelivered can still satisfy mailing when the address on file was correct under IRS rules.
• Know your circuit. In the Seventh and Ninth Circuits (and Tax Court outside the Third), late petitions are generally fatal with no equitable tolling. Elsewhere, tolling may be argued—but only with counsel and on specific facts.
• Plan the refund path early. If the petition window is gone, map full payment, Form 1040-X, and the refund-suit venue before collection hardens.

A short firm checklist

• On every notice of deficiency / 90-day letter, stamp the presumed mailing date and compute day 90 (or 150), rolling forward if day 90 falls on a weekend or holiday.
• Pull the account transcript and ask counsel whether Form 3877, PTR, or ACDS evidence of mailing is in dispute.
• Confirm the client’s last known address against IRS records before relying on non-receipt stories.
• If the petition is already late, do not file a doomed Tax Court petition for delay; discuss Flora payment, refund claim, and CDP with controversy counsel.
• Separate exam strategy from petition timing—appeals protests and 30-day letters do not pause the later §6213(a) clock once the notice of deficiency is mailed.

Where this fits for Tax Brew readers

Notice-of-deficiency calendars, transcript pulls and refund-claim packages need careful prep while signing professionals and counsel own the judgment calls. If your firm needs extra capacity on that preparation work, outsourced tax prep and bookkeeping support for US CPA firms can help. Email info@taxbrewglobal.com.

Check current guidance: this article summarizes Ed Zollars, Current Federal Tax Developments (September 24, 2026) analyzing Lindsey v. Commissioner, T.C. Memo. 2026-94 (filed September 24, 2026; Judge Jones), Sullivan & Cromwell Tax Policy Update (September 29, 2026), TaxCourtBlog coverage, Tilden v. Commissioner, 846 F.3d 882 (7th Cir. 2017), and IRC §§6212, 6213(a), 6511, 6532 and 7422. Confirm the full opinion and current Code before advising. This is general information, not tax or legal advice. Sources as of 14 October 2026.