Thread: A (Behind the IRS Curtain)
A tax-resolution practitioner notices the same thing every September: the firm’s phone volume doubles. Clients who have been quiet for months suddenly call in a single week saying “I got a letter from the IRS.” Different clients, different debts, different cities, but the letters all arrived within the same five-day window. The same pattern repeats every December, every August, and at the same low ebb every April. The clients are not coordinating; the IRS is. Most tax content describes IRS collection activity as continuous and reactive, like a machine running at constant speed. The actual collection function runs in waves tied to the federal fiscal year, quarterly Automated Collection System batch cycles, and the appropriations calendar in Washington, and the wave structure is predictable enough that a practitioner can mark their calendar.
This article walks the calendar. Not the marketing version where “the IRS is always watching” creates background anxiety, but the actual operational pattern under IRM 5.19 and the budget-cycle drivers that shape the year. Knowing the wave structure is operationally useful for taxpayers and tax-resolution practices alike, it changes when to expect contact, when collection silence is meaningful versus normal, and why the “I haven’t heard from the IRS in six months” experience is more common than the panicked tax-resolution advertising implies.
The wave pattern most taxpayers don’t realize exists
The empirical pattern is observable in any tax-resolution practice’s call-log data: collection-letter volume to taxpayers spikes in late summer (July through September), peaks again in mid-December, and bottoms in March and April. The same pattern shows up in published IRS Data Book statistics on collection-notice issuance and in the GAO oversight reports on Collection function workload (notably GAO-22-104719). The waves are not random; they are an emergent feature of how the IRS appropriates, schedules, and executes collection work across a calendar year. Once a taxpayer or practitioner sees the pattern, the “why now?” question about IRS letters answers itself.
The federal fiscal year basics
The federal fiscal year runs October 1 through September 30 (per 31 USC §1102), which differs from the calendar year that drives most private-sector budgeting. The IRS, like every federal agency, operates against annual performance metrics tied to that fiscal calendar. Enforcement targets, examination closures, collection-dollar yield, all of these are measured against the September 30 fiscal-year-end. Funding is appropriated by Congress on the same calendar (usually, when continuing resolutions don’t intervene), which means the IRS knows its operational budget for any given year on a schedule that runs October-to-October.
This produces a predictable intensification cycle. The third and fourth quarters of the federal fiscal year (April through September) are when the IRS works hardest to hit annual performance targets. Collection-letter volume rises accordingly. The first quarter of the new fiscal year (October through December) is when new appropriations land and new workload assignments roll out, typically with a brief operational lull before the next year’s intensification cycle begins.
ACS batch cycles
The Automated Collection System processes individual accounts in batches rather than continuously. Under IRM 5.19, specifically IRM 5.19.1 (Balance Due) and IRM 5.19.2 (Return Delinquency), ACS runs accounts through stages on a quarterly batch schedule: accounts that hit a particular notice threshold get the next letter in the sequence (CP14 → CP501 → CP503 → CP504 → LT11) at the next batch run. The batches don’t all run on the same day, and the IRS doesn’t publish the specific batch dates, but the quarterly rhythm is consistent and is documented at the procedural level in IRM 5.19.1.3 (notice issuance) and in TIGTA periodic reports on ACS workload distribution.
The practical consequence: a taxpayer assessed in March may not receive their first CP14 until June, because the March-assessment cohort batches through ACS at the next-quarter cycle. A taxpayer assessed in July may receive their CP14 within weeks because the agency is in fiscal-year-end mode and accelerating cycle times. The taxpayer doesn’t see the batch; the taxpayer sees the letter that arrives on a schedule that has more to do with ACS batch timing than with anything specific to their case.
Filing-season displacement
January through April is the lowest-volume window for collection letters every year. The IRS reallocates personnel from collection functions to return-processing during filing season, and the CP-series notice issuance slows accordingly. The slowdown is not stopping, ACS continues to run automated batches, and field collection ROs continue to work field cases, but the operational throughput decreases. Taxpayers who notice collection silence in March and April are observing this reallocation, not a meaningful change in case status.
For a taxpayer with an open IRS balance, the filing-season window is the right time to prepare. Documentation that needs to be assembled, financial statements that need to be drafted (Form 433-A or 433-B for collection cases), professional advice that needs to be obtained, all of it benefits from the predictable lull when the IRS is itself less likely to escalate. The filing-season window is also when a tax-resolution practice can take new client intake more deliberately, because the firm’s existing caseload generates fewer urgent calls.
Fiscal-year-end intensification
July through September is the opposite pattern. ACS batch cycles accelerate, field collection ROs work to close cases before September 30, and Final Notice of Intent to Levy letters (LT11 / Letter 1058) cluster in this window. The intensification is documented in TIGTA reports on Collection workload distribution and is visible in any tax-resolution practice’s call-log data. The taxpayer-side implication is that if collection contact is going to happen in a given calendar year, the late-summer window is when it’s most likely to happen.
A second smaller spike appears in December: ACS works through the late-year batch cycle, and certain Notice of Federal Tax Lien filings cluster as the agency closes out calendar-year items separate from the fiscal-year-end push. The December spike is shorter and less intense than the September spike, but it’s reliable enough that a practitioner who staffs around it gets less surprised than one who doesn’t.
What this means for the taxpayer
Collection silence in March and April is not your case being “closed” or “forgotten”, it’s calendar. The downside to misreading this is concrete: a taxpayer who interprets the spring lull as “the IRS dropped my case” relaxes their preparation, then receives a Final Notice of Intent to Levy in August with the 30-day Collection Due Process window already running and no documentation organized. The same case worked proactively in March, transcripts pulled, Form 433-A drafted, supporting documentation assembled, professional advice obtained, produces materially different options in August than the same case worked reactively in August itself.
Predictable spikes in late summer and mid-December mean predictable windows to be ready: pull your IRS account transcript via IRS Online Account or Form 4506-T, confirm your assessment dates and any tolling events, and have your documentation organized in advance. A taxpayer who treats the spring as the preparation window and the late summer as the response window operates with the IRS’s rhythm rather than against it. A taxpayer who only thinks about the IRS when a letter arrives is operating reactively in a system that announces its timing well in advance.
For tax-resolution practitioners, the operational implication is staffing: client-call volume is itself wave-driven, and a firm that staffs to the average call volume runs short in September and overstaffed in April. The firms that scale resources to match the calendar produce better client outcomes during the high-volume window and better economics during the low-volume window. The IRS’s calendar is not something to fight; it’s something to plan around.
The federal fiscal year is the rhythm. The ACS quarterly batches are the operational expression. The taxpayer experience of “letters in waves” is the visible output. Once the cycle is visible, the response is calibrated to it.
Authority: 31 USC §1102 (federal fiscal year definition); Inflation Reduction Act of 2022 §10301 (IRS supplemental funding); IRM 5.19 (Automated Collection System procedures); IRM 5.1 (General Field Collection); Pub 594 (The IRS Collection Process); IRS Operations Plan (annual public release); IRS Data Book (annual collection activity statistics); GAO-22-104719 (IRS Collection workforce and workload analysis); TIGTA reports on Collection workload distribution (periodic); OMB Circular A-11 (appropriations execution guidance); CP14 / CP501 / CP503 / CP504 / LT11 / Letter 1058 (collection notice sequence under IRC §6303 and §6330).