The IRS said “we mailed it.” The Tax Court said: prove it.

In Wales v. Commissioner, decided September 3, the IRS tried to shut down an innocent-spouse case over a determination notice it claimed to have mailed. It couldn’t produce the mailing log — and the court kept the case alive.

Every tax practitioner has had this conversation with a client: “I never got that letter from the IRS.” Usually, that’s the client’s problem. But a new Tax Court decision says it can just as easily be the IRS’s problem — and it shows exactly how that argument gets won.

What happened

In Dania Wales v. Commissioner (T.C. Memo. 2026-82, decided September 3, 2026), the taxpayer had filed a Form 8857 — the request for innocent spouse relief — back in August 2023. Then, nothing. For more than two years, no response from the IRS. So she did what the law allows: if the IRS hasn’t resolved your request within six months, you can petition the Tax Court directly. She did.

The IRS moved to dismiss. Their argument: we actually mailed you a Final Determination Notice by certified mail back in February 2025, and that started a strict 90-day clock to get to court — a clock that had long expired by the time she filed.

Where the IRS’s proof fell apart

To prove it mailed something, the IRS normally produces a USPS Form 3877 — the certified mailing log. It couldn’t produce one here. Instead, it offered a copy of the notice, a returned envelope marked “unclaimed,” and some USPS tracking data.

The problem: the actual envelope showed presorted first-class postage with no certified mail marking, and nothing in the tracking history stated the item had gone by certified or registered mail at all. The Tax Court held that none of this secondary evidence met the government’s burden of proof. If the IRS can’t prove proper mailing, the 90-day deadline was never triggered. Motion to dismiss: denied.

What this means for you

1. The IRS has to follow its own procedures. When the agency says “we sent the notice,” that’s a claim — and claims need proof. Sloppy IRS recordkeeping can keep your window to fight open.
2. Deadlines still run the whole game. This taxpayer won because the clock never started. In most cases the IRS does mail things properly, and the 90-day clock is brutally strict — miss it and Tax Court is off the table. Never sit on IRS mail.
3. “I never got it” isn’t a strategy — it’s a fact pattern a professional has to develop. This case was won on postage markings and mailing logs, not on vibes. That’s the difference representation makes.

Alex Volkov, CPA is a New York-licensed CPA with over two decades in accounting, focused on resolving IRS tax problems — back taxes, liens, levies, garnishments, and audits — for individuals and businesses nationwide.