Issues

QBI Deduction: How To Defend Your §199A Write-Off in Tax Court

The IRS cut or denied your 20% QBI deduction and now you owe. The fight is technical—but it's winnable, and most of it comes down to one number.

The IRS cut your 20% qualified business income deduction—or denied it outright—and now a notice says you owe. Maybe the examiner called your business a "specified service" and zeroed the deduction. Maybe they said you have no W-2 wages, so the deduction shrank to a fraction of what you claimed. Maybe they decided your activity isn't a real business at all, or simply recomputed your taxable income and the deduction fell with it.

Here is the reassuring part: the qualified business income (QBI) deduction is one of the most mechanical deductions in the tax code. It is mostly arithmetic driven by a handful of defined terms. That means a large share of these disputes are not really arguments about the law at all—they are threshold errors, wage-figure errors, and misclassifications that resolve the moment the right form is run on the right numbers. The fight is technical, but technical is winnable.

This is the substantive merits guide for the pro se Schedule C filer, partner, or S-corporation shareholder defending the IRC § 199A deduction after the IRS knocks it down. It explains what § 199A actually gives you, the single number that decides whether any of the limits even apply, the two big merits fights (the W-2 wage limit and the "specified service" label), what counts as QBI in the first place, how the dispute travels from an audit letter to US Tax Court, and exactly what is at stake in dollars. It is a close companion to How To Prove Your Business Expenses to the IRS—because your QBI flows straight out of the Schedule C net profit that article teaches you to defend.

What the QBI Deduction Is

The QBI deduction lets the owner of a pass-through business—a business whose profits "pass through" to your personal return rather than being taxed at the company level—deduct up to 20% of the business's net profit. It covers sole proprietors who file a Schedule C, partners in a partnership, S-corporation shareholders, and certain trust and estate beneficiaries. (C corporations don't get it; they got the flat 21% corporate rate instead.)

Three plain-English points matter before anything else, because they shape what's worth fighting for.

It's a "below-the-line" deduction—it does not cut your AGI. The statute computes your taxable income first, then subtracts the QBI deduction (§ 199A(e)(1)). So it lowers taxable income but not adjusted gross income, and—this surprises people—you get it whether you itemize or take the standard deduction. It sits on top of the standard deduction, not instead of it.

It does not reduce your self-employment tax. Section 199A(f)(3) allows the deduction "only for purposes of this chapter"—the income-tax chapter. Self-employment tax lives in a different chapter of the Code, so QBI never touches it. A $10,000 QBI deduction lowers your income tax, but your roughly 15.3% self-employment tax bill is computed as if the deduction didn't exist.

The starting math is simple—20% of your net business profit—and stays simple unless your income is high. Two limits can shrink or zero out the deduction, but they switch on only if your taxable income is above a threshold (explained below). Below that threshold, it really is just 20%. That single fact—where your taxable income sits relative to the threshold—decides almost everything about your case.

What Changed for 2026 and Beyond

The 2025 tax law—the One Big Beautiful Bill Act (OBBBA, P.L. 119-21), at § 70105—made three changes to § 199A. All three are enacted, current law, and all three take effect for tax years beginning after December 31, 2025 (so 2026 returns, filed in 2027):

§ 199A is now permanent. Under the prior law, the QBI deduction was scheduled to disappear after 2025. OBBBA struck that expiration entirely. There is no longer a sunset date—the deduction is permanent.
The phase-in band widened. The income range over which the limits gradually kick in grew from $50,000 (single) / $100,000 (joint) to $75,000 / $150,000. More owners now land inside the gradual zone instead of hitting the full limit.
A new $400 minimum deduction. If your total QBI from "active" businesses you materially participate in is at least $1,000 for the year, your deduction is the greater of the normal computation or $400. It's a small floor aimed at very-low-QBI owners.

One discipline point that matters for your dispute. Most QBI fights in 2026 concern earlier tax years—2021 through 2024—because audits lag. (The IRS generally has 3 years from when you filed to assess additional tax, though that window can stretch longer in some cases—see Understanding IRS Statutes of Limitations.) The rules that govern your case are the rules for the year under exam, not today's. So if your dispute is about a 2023 return, the $75,000/$150,000 band and the $400 floor do not apply to it—those start in 2026. Pin down the year the IRS is examining, and apply that year's figures. The boxes below give you the verified numbers for the recent years.

The Threshold: The One Number Your Whole Case Turns On

Everything in § 199A turns on whether your taxable income (figured before the QBI deduction) is below, inside, or above a threshold amount that adjusts for inflation each year (§ 199A(e)(2)).

Below the threshold. Simple. You get 20% of QBI, with no W-2 wage limit, and a "specified service" business is fully allowed like any other. This is the world of the one-page Form 8995, the "simplified computation." Most pro se disputes live here, and most of those are arithmetic.

Above the top of the phase-in range. Both limits apply in full: the W-2 wage / UBIA limit caps each business's deduction (the first big fight, below), and a "specified service" business is fully disallowed—$0 (the second big fight).

Inside the phase-in range (between the threshold and the top of the range): both limits phase in proportionally. This is the messy middle, computed on the longer Form 8995-A.

Here are the verified figures for the two most recent years. Confirm the figure for your year against that year's IRS inflation-adjustment revenue procedure—they move annually.

Tax year	Filing status	Threshold	Top of phase-in range
2025	Single / Head of Household / other	$197,300	$247,300
2025	Married filing jointly	$394,600	$494,600
2026	Single / Head of Household / other	$201,750	$276,750
2026	Married filing jointly	$403,500	$553,500

Notice the band itself: in 2025 it spans $50,000 (single) and $100,000 (joint)—the old width. In 2026 it spans $75,000 (single) and $150,000 (joint)—the OBBBA widening. For years before 2025, use that year's threshold—the figure appears in the instructions to Form 8995-A and in that year's IRS inflation-adjustment revenue procedure. Recent single/joint thresholds were $191,950 / $383,900 for 2024, $182,100 / $364,200 for 2023, $170,050 / $340,100 for 2022, and $164,900 / $329,800 for 2021.

So before you argue anything, find your taxable income for the year in dispute and place it on this map. If you were below the threshold, neither big fight applies to you, and the IRS's adjustment is almost certainly either an arithmetic recompute or a "is this even a business" challenge—skip ahead to the QBI and trade-or-business sections. If you were above it, read the next two sections closely.

Fight #1: The W-2 Wage / UBIA Limit

For a taxpayer above the threshold, the deduction for each business is capped at the greater of:

(a) 50% of the W-2 wages the business paid, or
(b) 25% of the W-2 wages, plus 2.5% of the UBIA of qualified property.

(§ 199A(b)(2)(B).) The business's deduction is then the lesser of 20% of its QBI or this cap. "UBIA" stands for unadjusted basis immediately after acquisition—essentially the original cost of depreciable business property, before any depreciation is subtracted.

The sole-proprietor-with-no-employees trap. Read prong (a) again. If your business has no employees, it paid $0 in W-2 wages, and 50% of zero is zero. Above the threshold, that can wipe out the deduction—unless prong (b)'s UBIA leg saves you. A business with significant equipment or real estate can clear the limit on the 2.5%-of-cost prong even with little or no payroll, which is why a property-heavy operation survives where a pure-services solo shop does not. (Note: paying yourself as a sole proprietor doesn't help here—an owner's draw is not a W-2 wage, and neither are payments to independent contractors you issue a 1099 to.)

What counts as "W-2 wages" (§ 199A(b)(4) and Treas. Reg. § 1.199A-2): wages the business reported on W-2s, including elective deferrals and designated Roth contributions. But two conditions bite. The wages must be properly allocable to the QBI—that is, the wage expense was actually taken into account in computing the qualified income of that business. And the W-2s must have been reported to the Social Security Administration on time; late-filed W-2s are excluded.

What counts as UBIA (§ 199A(b)(6) and the same regulation): depreciable tangible property—equipment, machinery, buildings—held and used by the business at year-end, whose "depreciable period" hasn't run out. UBIA is generally the original cost basis, not reduced by depreciation. That's the key feature: a landlord-style or asset-heavy business gets to count 2.5% of the full original cost of its buildings and equipment, which is how low-payroll businesses still clear the limit.

Where the IRS and taxpayers actually fight here: which wages are "properly allocable to QBI," whether the W-2s were timely filed with the SSA, and the UBIA math—basis figures, placed-in-service dates, and whether an asset's depreciable period has ended. This is a live, litigated issue, not a settled one. The leading reported case on the wage prong, Savage (discussed in the cases section), turned on exactly which wages count.

One rescue worth knowing about: aggregation. If you own several related businesses, the regulations let you aggregate them and combine their W-2 wages and qualified property for this limit—so a high-profit, low-wage business can borrow wage capacity from a sister business that has payroll. You report it on Schedule B of Form 8995-A, and once you aggregate you generally have to keep doing so in later years. It's a higher-income, multi-entity move, but it is often what saves the deduction above the threshold.

Fight #2: The "Specified Service" Label (SSTB)

A specified service trade or business—"SSTB" for short—is a business in certain personal-service fields. The stakes are blunt: above the threshold, an SSTB gets $0 QBI deduction. Below the threshold, an SSTB is fully allowed like any other business. Inside the range, partial. So this label only matters for higher-income owners—but for them it's all-or-nothing, which makes it one of the most contested points in the whole area.

The list of SSTB fields (§ 199A(d)(2), incorporating the service fields of § 1202(e)(3), and fleshed out by Treas. Reg. § 1.199A-5): health, law, accounting, actuarial science, performing arts, consulting, athletics, financial services, brokerage services, investing and investment management, trading, and dealing in securities—plus a "reputation or skill" catch-all. The regulation then narrows each field. "Consulting," for instance, means giving professional advice and counsel, and it expressly excludes sales and training. "Health" covers physicians, nurses, and dentists but excludes health clubs and the manufacture or sale of pharmaceuticals and devices.

The engineering and architecture carve-out. Here's a confusion the IRS sometimes gets backward. The underlying § 1202 list does name engineering and architecture—but § 199A specifically excludes engineering and architecture from the SSTB definition. Engineers and architects are not SSTBs for QBI purposes. If an examiner labeled an engineering or architecture firm an SSTB, that is a straight legal error worth pointing to the statute on.

The "Reputation or Skill" Catch-All Is Much Narrower Than It Sounds

This is the strongest merits argument for many skilled solo owners, so understand it precisely. The statutory phrase reaches a business "where the principal asset . . . is the reputation or skill of 1 or more . . . employees." Read loosely, that sounds like it could swallow any business that depends on a talented owner—and examiners sometimes argue exactly that.

It does not. The regulation, Treas. Reg. § 1.199A-5(b)(2)(xiv), cuts the catch-all down to just three fact patterns:

(A) receiving income for endorsing products or services;
(B) licensing or receiving income for the use of your image, likeness, name, signature, voice, trademark, or other symbols associated with your identity; or
(C) receiving appearance fees—for showing up at an event, or on radio, television, or other media.

That's the whole list. The catch-all reaches celebrity-style income—endorsements, name-and-likeness licensing, and appearance fees—and nothing more. A skilled tradesperson, a freelance designer, a one-person shop whose work depends on the owner's talent is not an SSTB just because the work takes skill. So if an examiner zeroed your deduction on a loose "it's all about your personal reputation and skill" theory, the regulation is on your side: unless your income fits one of those three patterns, the catch-all doesn't apply.

The De Minimis Escape Hatch

Even a business with some SSTB activity can escape the label entirely. Under Treas. Reg. § 1.199A-5(c)(1), a business with gross receipts of $25 million or less is not an SSTB if less than 10% of its gross receipts come from SSTB-type services. (For a business with gross receipts over $25 million, the regulation substitutes 5% for 10%.) So a mostly-non-SSTB business with a small slice of service income isn't tainted by that slice.

What Even Counts as QBI

Before any limit applies, the income has to qualify as QBI in the first place. QBI is the net amount of qualified income, gain, deduction, and loss from a qualified trade or business (§ 199A(c)(1)). Two gates and a short exclusion list do most of the work.

Gate one: it has to be a real trade or business. The regulation defines "trade or business" for § 199A as a trade or business under IRC § 162 (Treas. Reg. § 1.199A-1(b)(14)). That single cross-reference ties QBI to the entire body of § 162 trade-or-business law. So the threshold question "is this even a business?"—the same question at the heart of a hobby-loss fight—is a QBI question too. A sideline with no profit motive, or pure passive investing, doesn't produce QBI because it isn't a § 162 trade or business.

The foundational authorities here are two Supreme Court cases that predate § 199A by decades but supply the rule it imports. In Commissioner v. Groetzinger, 480 U.S. 23 (1987), the Court held that a full-time gambler betting for his own account was in a trade or business, because the activity was "pursued full time, in good faith, and with regularity, to the production of income for a livelihood." And in Higgins v. Commissioner, 312 U.S. 212 (1941), the Court held that merely managing your own investment portfolio—no matter how large or how much effort it takes—is not a trade or business. These aren't § 199A cases; they're the trade-or-business cases § 199A quietly stands on.

Gate two: it has to be the right kind of income. QBI must be effectively connected with a U.S. trade or business and included in your taxable income (§ 199A(c)(3)).

What QBI excludes (the items the IRS will say you wrongly swept in):

Capital gains and losses, and most dividend- and interest-type investment income not tied to the business (§ 199A(c)(3)(B)). This is Higgins in statutory form—passive investment return isn't business income.
An S-corporation owner's reasonable compensation—the W-2 wages the corporation pays you are not QBI (§ 199A(c)(4)). This is the bridge to the worker-classification and reasonable-comp fight: the more the IRS recharacterizes as reasonable wages to you, the less is left as QBI.
Guaranteed payments to a partner for services (§ 199A(c)(4)).

The negative-QBI carryover. If your net QBI across all your businesses is negative for a year, it doesn't vanish—it's carried to the next year as a loss that reduces that year's QBI (§ 199A(c)(2)). So a bad year follows you forward, and an IRS adjustment that creates or enlarges a negative-QBI year can quietly shrink the next year's deduction too. A carryover shows up on the prior year's Form 8995 or 8995-A, so compare the years if the IRS's figure doesn't match yours—and check whether a carryover is part of what the IRS changed.

Rentals: When a Landlord Gets the QBI Deduction

A rental qualifies for QBI only if it rises to the level of a § 162 trade or business (or fits a narrow self-rental rule). Many small landlords assume every rental automatically qualifies. It doesn't.

There are two ways to get there, and missing the first doesn't cost you the second.

The safe harbor (Rev. Proc. 2019-38). The IRS published a safe harbor: meet all its requirements and your rental real estate enterprise is treated as a trade or business solely for § 199A. You have to satisfy, for the year:

Separate books and records for the rental enterprise;
250+ hours of rental services (for an enterprise four or more years old, 250+ hours in any three of the prior five years);
Contemporaneous records—logs of hours, dates, descriptions, and who did the work (this records requirement doesn't apply to years before 2020); and
A signed statement attached to a timely-filed return for each year you rely on the safe harbor.

"Rental services" that count include advertising, leasing, screening tenants, collecting rent, daily operation and maintenance, and supervising workers. They do not include arranging financing, reviewing financials, or—watch this one—travel time to and from the property. The safe harbor also can't be used for a home you use as a residence, or for property under a triple-net lease.

The safe harbor isn't the only path—and this is the point landlords miss. The revenue procedure says in plain terms that failing the safe harbor "does not preclude a taxpayer . . . from otherwise establishing that an interest in rental real estate is a trade or business for purposes of section 199A." So a landlord who can't hit 250 hours can still win by proving a § 162 trade or business the old-fashioned way—on the facts and circumstances of how regularly and continuously the rental was operated. The safe harbor is a shortcut, not a gate. For the full picture of how rental activity is characterized, see How To Deduct Rental and Passive-Activity Losses.

The Overall 20% Cap

One more limit sits on top of everything: the total QBI deduction can never exceed 20% of (your taxable income minus your net capital gain) (§ 199A(a)). Even if every business-level computation is generous, this cap controls.

This catches people whose income is mostly not business income. If you have a big QBI but most of your taxable income is wages or capital gains, this overall cap—not the business-level math—may be what limits your deduction. It's also a common reason the IRS recomputes QBI: any other adjustment that changes your taxable income changes this cap, and the deduction moves with it. If the IRS adjusted some unrelated item and your QBI dropped as a side effect, this cap is probably why.

How These Disputes Reach Tax Court

A § 199A adjustment arrives the same way other deduction adjustments do.

A CP2000 notice is less common for QBI directly—the deduction is computed, not matched against a 1099—but a CP2000 income change cascades into a QBI recompute.
More often it's an examination (by mail or in person), producing an examiner's report (Form 4549) and a 30-day letter proposing the disallowance. See How To Respond to an IRS Audit.
The 30-day letter offers you a protest to the IRS Independent Office of Appeals—a separate office, staffed by people who didn't run your audit, that can settle a documentary QBI dispute with no filing fee and no court. For a computational issue like this, it's often the cheapest place to win. See How To Request an IRS Appeals Conference.
If Appeals doesn't resolve it (or you let the 30-day window lapse), the IRS issues a Notice of Deficiency—the 90-day letter.

The Notice of Deficiency is your ticket to Tax Court. Under IRC § 6213, you have 90 days from the date on the notice (150 days if it's addressed outside the US) to file a petition. Miss it and you lose the chance to fight before paying. See You Just Got a 90-Day Letter From the IRS and How To File Your Tax Court Petition.

Which Notice Am I Holding?

Before anything else, identify your notice, because only one of them starts a clock you cannot extend.

A CP2000, an examination report (Form 4549), or a 30-day letter is a proposed change. There is no 90-day Tax Court clock yet. Respond by the deadline printed on the letter—usually about 30 days—with your corrected computation and records. This is the cheapest place to win. See How To Respond to an IRS Audit.
A Notice of Deficiency (often Letter 3219; it will say "Notice of Deficiency" and give a last date to petition the Tax Court) is the 90-day letter. The clock is running, and that deadline is firm.

If you're not sure which you have, look for the words "Notice of Deficiency" and a stated last date to petition. If they're not there, you're almost certainly still at the audit stage—respond on the merits and try to keep the case out of court.

Verify the IRS's Numbers Before You Fight

Because QBI is so mechanical, the single highest-value first step is checking the IRS's arithmetic, not arguing the law. A large share of QBI "disputes" are computation errors that dissolve once the right form is run on the right figures.

Find the exact line the IRS changed. Get the Form 4549 (the examination report) and the Notice of Deficiency, and pin down which part of § 199A moved your deduction. On the Form 4549 the QBI change appears as an adjustment to your income, followed by a short examiner's explanation of why—read that explanation, because the dollar figure alone won't tell you whether the issue is the threshold, the wage limit, the SSTB label, or a trade-or-business denial. Was it the threshold (did they recompute your taxable income)? The W-2 wage limit? An SSTB reclassification? A trade-or-business denial? Or a recompute flowing from some other adjustment through the overall 20% cap? Each one is a different argument, and the explanation tells you which fight you're actually in.

Pull your transcripts. Get your account transcript and your wage-and-income transcript—both are taxpayer-accessible through IRS.gov's Get Transcript tool. The account transcript shows what's actually been assessed and when; the wage-and-income transcript shows the W-2 and 1099 figures the IRS has on file, which is exactly what you need to confirm the wage numbers behind the W-2 limit. See How To Get and Read Your IRS Transcripts and How To Read IRS Transcript Codes.

Re-run the form. Redo the math on Form 8995 if you were below the threshold (the simplified computation) or Form 8995-A if you were above it, an SSTB, or aggregating multiple businesses. Running the correct form on verified numbers is, more often than not, the entire case.

The Full Exposure: Deficiency, Penalty, and Interest

Size the whole dispute before you decide how hard to fight. The disallowed deduction is only the first layer.

The deficiency. Disallowing a QBI deduction raises your taxable income by the deduction amount; the extra tax is that increase times your marginal rate—not the deduction itself. A disallowed $10,000 QBI deduction for someone in the 22% bracket is roughly $2,200 of additional tax, not $10,000.

The accuracy-related penalty—and a QBI-specific trap. On top of the tax, the IRS often asserts a 20% accuracy-related penalty under IRC § 6662, for negligence or a "substantial understatement." For most individuals, an understatement is "substantial" only if it exceeds the greater of 10% of the correct tax or $5,000. But § 6662(d)(1)(C) lowers that 10% to 5% for any taxpayer who claims a § 199A deduction. So QBI claimants face an easier-to-trip penalty threshold than other taxpayers—a concrete reason to get the computation exactly right and keep your substantiation. The penalty-defense toolkit, including reasonable cause and good faith, is in How To Fight the IRS Accuracy Penalty.

The supervisory-approval defense. A § 6662 penalty is invalid unless the examiner's immediate supervisor personally approved it in writing before assessment (IRC § 6751(b)). A final regulation (T.D. 10017, December 2024) sets a bright-line deadline for that approval. It's an independent defense worth checking: if the IRS can't prove timely written approval, the penalty can fall on that ground alone, regardless of the merits.

Interest. Interest runs on the deficiency from the original due date of the return until you pay, at the IRS underpayment rate—recently around 7–8%, compounded daily. That leg quietly grows the longer the case runs. See How Interest Works on Your IRS Tax Debt.

A Worked Example

Suppose the IRS reclassified your consulting-adjacent business as an SSTB for 2023, when your taxable income was above the threshold, and disallowed the whole $12,000 QBI deduction you claimed. You're in the 24% bracket.

Deficiency: $12,000 × 24% ≈ $2,880 of additional tax.
Accuracy penalty: if the understatement is "substantial"—and remember the QBI 5% threshold makes that easier to reach—a 20% penalty on the underpayment adds up to about $576.
Interest: on the roughly $3,450 of tax-plus-penalty, running from the 2023 return's April 2024 due date through a mid-2026 resolution—about two years—at the IRS underpayment rate of roughly 7–8% compounded daily, interest adds on the order of $500–$600, and it keeps climbing each month the balance stays unpaid.

So a "$12,000 deduction" dispute is really about $4,000 of exposure once the penalty and interest are stacked on the tax. And the strongest single move against it is the narrow "reputation or skill" argument from Fight #2: if your income doesn't fit one of those three celebrity-style patterns, the SSTB label—and the whole bill—may not survive.

Who Has the Burden

In Tax Court the IRS's determination is presumed correct, and the deduction is yours to prove. Tax Court Rule 142(a) puts "the burden of proof upon the petitioner." IRC § 7491 can shift a factual issue to the IRS if you produce credible evidence and met the substantiation and recordkeeping rules—but most QBI disputes are decided on the documents or as pure questions of law (as Savage was), so the shift rarely changes the result. One piece does sit with the IRS: under § 7491(c), the IRS carries the burden of production on the penalty.

What the Cases Tell Us

Section 199A is post-2018 law, so reported merits precedent is thin. Be honest about that—there is no body of taxpayer-favorable § 199A case law to point to, and you should be wary of any source that implies otherwise. The one on-point reported merits opinion is Savage; the two Supreme Court cases supply the trade-or-business foundation, not § 199A holdings.

Savage v. Commissioner, 165 T.C. No. 5 (2025) — This is the leading reported § 199A merits decision, and it's important to frame it accurately. The taxpayers were represented by counsel, not pro se, and they lost: the Tax Court ruled for the Commissioner. Two shareholders of S corporations (two of which were cannabis businesses subject to § 280E, the rule that disallows deductions for trafficking in controlled substances) claimed § 199A deductions and treated all the wages their companies paid as "W-2 wages"—including wages whose deduction § 280E disallowed. The court held that for the W-2 wage limit, only wages that are actually deductible in computing QBI count, ruling that the Commissioner "correctly applied I.R.C. § 199A with respect to the wages at issue." The holding is specific to the § 280E cannabis context, but the method—reading the statute's text first to decide what "W-2 wages" means—is what makes it instructive. Use Savage for what it actually shows: that the W-2 wage limit is a live, litigated § 199A issue reaching Tax Court, and that "W-2 wages" means wages truly allowable in computing the business's qualified income. It is not a taxpayer win, and it is not a pro se case.

Commissioner v. Groetzinger, 480 U.S. 23 (1987) — The foundational trade-or-business case. A full-time gambler was held to be in a trade or business because the activity was pursued "full time, in good faith, and with regularity," with continuity and a profit motive. It supplies the "is this a trade or business?" standard that § 199A imports through § 162—the gate every QBI claim must clear. Not a § 199A case.

Higgins v. Commissioner, 312 U.S. 212 (1941) — The mirror image. Managing your own investment portfolio, however large the effort, is not a trade or business. This is why passive investing produces no QBI and why investment dividends and interest are excluded. Not a § 199A case, but the reason a large slice of the QBI exclusions exist.

If the IRS Is Actually Right

Run the analysis honestly first. If your taxable income was above the threshold and your business really has no W-2 wages and no qualifying property, the wage limit may legitimately gut the deduction. If your income genuinely fits an endorsement or appearance-fee pattern, the SSTB label may stick. If your activity was a sideline with no real profit motive, it may not be a § 162 business at all. When the deduction is correctly disallowed, point your energy where it can still help:

Fight the penalty, not the tax. Even when the deficiency is right, the accuracy penalty can often be removed for reasonable cause and good faith—an honest, reasonable misreading of these genuinely complex rules is a real argument—or knocked out on the § 6751(b) supervisory-approval defense.
Fix it going forward. If the issue is a computation error that also affects an open year you can still amend, an amended return may correct it outside litigation.
Deal with what you owe. If you can't pay, you have options: an installment agreement, currently not collectible status if paying would leave you unable to cover basic living costs, or an offer in compromise.

The Path: From Notice to Tax Court

Here is how the dispute moves and where it usually ends:

Respond to the audit or CP2000. Send your corrected Form 8995 or 8995-A, your transcripts, and the records behind the wage and business-income figures to the exact address or fax on your notice, by the deadline printed there. Keep a complete copy and proof of delivery. Most disputes that resolve, resolve here. See How To Respond to a CP2000 Notice.
Try IRS Appeals. If the 30-day letter doesn't resolve it, file a protest to the IRS Independent Office of Appeals before the case ever reaches court. Appeals is free, informal, and handled by someone independent of your auditor—and for a clean computational QBI dispute it's frequently where the matter ends. See How To Request an IRS Appeals Conference.
Notice of Deficiency. If it isn't resolved, the IRS issues the 90-day letter. Under Section 6213, you have 90 days from the date on the notice (150 days if addressed outside the US) to file a petition in US Tax Court. This deadline cannot be extended, and filing in time stops assessment and collection while the case is pending. See How To File Your Tax Court Petition.
Usually a small case. Most pro se QBI deficiencies fall under the $50,000 small-case threshold, so you can elect the simplified ("S case") procedure—informal, plain-English, no rigid rules of evidence. The trade-off is that an S-case decision is final and sets no precedent. See Small Case or Regular Case: Which Should You Choose.
Filing fee and waiver. The fee is $60, with a waiver available if you can't afford it.
Most cases settle. Most (76%) of Tax Court cases close by settlement, and more than 99% resolve without a trial. Because QBI is documentary and computational, producing a clean, correct computation to IRS Counsel often produces a stipulated decision. Cases typically take 6-18 months to resolve.
If the 90 days lapsed: audit reconsideration. If the petition window passed and the tax was assessed, the fallback is audit reconsideration—asking the IRS to reopen with the computation and records you can now produce. It's discretionary, but it works well for purely documentary issues like this one.

Get Help

Around 89% of Tax Court petitioners represent themselves, and a documentary, computational QBI dispute can be well suited to it. But be candid about the odds—the represented win rate is higher (about 12% pro se versus about 23% represented in the most recent data)—and some situations call for help: an above-threshold case with aggregation across multiple businesses, a large penalty, or several years at once.

If your income is at or below 250% of the poverty line and your dispute is at or below $50,000, you may qualify for free representation through a Low-Income Taxpayer Clinic—they handle exactly these cases. For more complex situations, see When To Get Professional Help With Your Tax Dispute.

Resources

Statute and regulations:

IRS forms:

Cases cited:

Savage v. Commissioner, 165 T.C. No. 5 (2025) (U.S. Tax Court, DAWSON)
Commissioner v. Groetzinger, 480 U.S. 23 (1987)
Higgins v. Commissioner, 312 U.S. 212 (1941)

Companion articles on TaxCourtHelp:

This article is for informational purposes only and does not constitute legal or tax advice. For advice specific to your situation, consult a qualified tax professional or attorney.