The Treasury Inspector General for Tax Administration counted the mail the Internal Revenue Service sent to taxpayers who had not filed a return, and the swing was stark: zero notices in fiscal year 2023, 1.68 million in fiscal year 2024, and 3.16 million in fiscal year 2025. Almost the entire increase traces back to one group of taxpayers: those still missing a return for tax year 2023. For a household that has gone a year or more without filing, the numbers describe a program that sat idle for a full fiscal year and then came back running at a scale it had never reached before.
TIGTA’s Count: Zero Notices, Then 1.68 Million, Then 3.16 Million
The figures come from a review published by the Treasury Inspector General for Tax Administration, the IRS’s independent watchdog, titled Trends in Compliance Activities Through Fiscal Year 2025. The report, numbered 2026-3S0-045, was issued August 26, 2026, and it tracks IRS enforcement and compliance activity across three fiscal years side by side.
In fiscal year 2025, the report counts 3,157,055 nonfiler notices sent, up from 1,679,141 in fiscal year 2024 and zero in fiscal year 2023, when the relevant notice programs were not issuing mail at all. TIGTA frames the increase as the continuation of a phased restart, with mailings resuming in fiscal year 2024 at just over half of last year’s total before climbing again the following year as more of the paused inventory worked back into circulation. The report does not describe fiscal year 2023 as a policy choice to stop pursuing nonfilers; it describes a notice pipeline that had gone quiet and then had to be rebuilt in stages, which is part of why the increase shows up over two consecutive years rather than in a single jump.
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Why Tax Year 2023 Accounts for Nine of Every Ten Notices
Of the 3.16 million notices sent in fiscal year 2025, 2,922,671 of them — roughly nine in ten — concerned a single tax year: 2023. The remaining notices spanned five earlier tax years, from 2018 through 2022, in progressively smaller numbers the further back the year, and reflect the program working through older unfiled returns only after the larger 2023 batch had already gone out. For someone who missed filing a 2023 return specifically, the odds of receiving a notice about that year were higher last year than in any of the three years TIGTA reviewed, simply because that year’s batch dwarfed every other year’s combined.
What a Nonfiler Notice Actually Says
A nonfiler notice is not a bill. It is the IRS’s written record that its systems show no return filed for a specific tax year, matched against income documents the agency already has on file, such as W-2s, 1099s, and similar third-party reporting. The letter names the tax year in question and asks the recipient to either file the missing return or explain why none is owed, usually within a set number of days. What happens after a notice goes unanswered is a separate process with its own rules; the notice itself is only the opening step, and the volume TIGTA counted measures how many of those opening letters went out, not how many cases moved further from there.
A Second TIGTA Review Flags Gaps in Nonfiler Case Tracking
A second, separate TIGTA review, released September 4, 2026, examined a related but distinct piece of the nonfiler picture: high-income cases opened under a nonfiler initiative the IRS launched in February 2024. That review found close to 39,000 high-priority cases still sitting in first-notice status as of mid-2025, representing about $15.7 billion in potential tax assessments, because IRS collection managers had asked in March 2024 that final notices be delayed over concerns about available resources. The same review found that the IRS’s Nonfiler Executive Steering Committee, the body meant to coordinate nonfiler enforcement across the agency, had not met since September 2020, and that the agency does not separately track how many staff hours go toward nonfiler cases versus other enforcement work.
That second review also put a dollar figure on why any of this matters at scale: the IRS estimates the gross tax gap, the difference between tax owed and tax paid voluntarily and on time, at $696 billion for tax year 2022 alone, with roughly $63 billion of that, about nine percent, attributed to people who simply never filed. The nonfiler notice count sits inside that larger number as one of the few tools the IRS has for closing it — a mailed letter is a comparatively cheap first step compared with an audit or a collection case.
How the Notice Surge Fits Into the IRS’s Broader Enforcement Numbers
The notice count itself does not say whether any individual letter was accurate, or whether the household that received it actually owed a return. It measures mail volume — a signal that the notice pipeline, after standing empty for a full fiscal year, is now moving at closer to full capacity. TIGTA’s report puts that pipeline in a wider context: total IRS enforcement revenue reached a historic $98.7 billion in fiscal year 2024 before slipping to $93.8 billion in fiscal year 2025, a decline the report attributes mainly to a 35 percent drop in examination-related revenue even as nonfiler notice mail climbed. Read against that backdrop, the jump in nonfiler notices looks less like an isolated spike and more like one enforcement channel picking up work as another slowed.
The Step Most Households Skip After a Notice Arrives
The volume shift TIGTA counted plays out one letter at a time: a household opens a notice about a prior tax year and has to figure out what it actually changes, separate from anything already happening with that year’s refund. When a notice touches a return that also had a refund pending, sorting out the notice and tracking down the refund become two different problems handled through two different parts of the IRS.
The IRS Refund Recovery Kit walks through a notice decoder for reading exactly what a given letter is asking for, and the refund-trace steps built around Form 3911 for a refund that has gone missing after a return was flagged.
See the notice decoder in The IRS Refund Recovery Kit.
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