What it is
TL;DR§199A gives pass-through owners up to a 20% deduction on qualified business income. Owners of specified service trades or businesses (SSTBs), doctors, lawyers, accountants, consultants, financial advisors, lose the deduction entirely above income thresholds. Smart compensation, entity, and aggregation planning preserves a meaningful chunk.
For 2026, the §199A SSTB phase-out begins at roughly $241,950 (single) / $483,900 (joint) of taxable income and ends $50k/$100k higher. Above the ceiling, an SSTB gets zero §199A deduction.
Below the ceiling, the deduction is meaningful. A dentist couple with $480k of joint taxable income can preserve a $50,000+ deduction simply by managing where they land in the phase-out range.
Who it's for
Owners of SSTB pass-throughs whose taxable income hovers in or near the phase-out range, and owners of mixed SSTB/non-SSTB operations where aggregation or separation matters.
- ✓Medical, legal, and accounting practice owners filing jointly with $400k-$700k of taxable income
- ✓Solo professionals with side investments or non-SSTB activities
- ✓Practice owners with W-2 spouses pushing them just over the phase-out
- ×Practice owners far above the phase-out ($800k+ joint), almost no §199A benefit available
- ×Practice owners well below the phase-out, already getting full deduction
- ×Pure SSTB single-entity operations with no separable non-SSTB activity
How it works
1. Manage taxable income with retirement and HSA
The phase-out is based on taxable income. A cash balance plan contribution, mega backdoor Roth conversion choice, or HSA contribution can move taxable income out of the phase-out range and restore the deduction.
2. Tune S-corp owner W-2 thoughtfully
Higher W-2 reduces QBI; lower W-2 increases QBI but risks §1366 reasonable-compensation scrutiny. The optimum sits at the lowest defensible reasonable comp, see the reasonable comp piece.
3. Separate non-SSTB activities into distinct entities
The de minimis rule (§1.199A-5(c)(1)(i)) treats a trade or business as not SSTB if SSTB activities account for ≤ 10% (or ≤ 5% for businesses with gross receipts over $25M) of gross receipts.
For a practice with a meaningful product or non-SSTB service line, structurally separating it can preserve §199A on the non-SSTB stream.
Anti-abuse rules under §1.199A-5(c)(2) prevent crack-and-pack structures that simply spin off administrative or back-office functions to non-SSTB entities owned 50%+ by the SSTB. The separated activity must be a real, standalone trade or business.
4. Make the aggregation election when beneficial
Common ownership of multiple non-SSTB pass-throughs (e.g., a dentist with three locations each in its own LLC) can elect under §1.199A-4 to aggregate, smoothing W-2 wage limitations and UBIA constraints.
A worked example
Dr. Sahota and her spouse have joint taxable income of $530,000 in 2026, $50,000 above the SSTB phase-out cliff. Dr. Sahota's S-corp QBI is $310,000. With no planning, she gets $0 of §199A deduction.
| No optimization | After planning moves | |
|---|---|---|
| Joint taxable income | $530,000 | $482,000 |
| Cash balance plan contribution | $0 | $48,000 |
| §199A deduction (after phase-out) | $0 | $38,000 |
| Federal tax saved (24% bracket) | $0 | $9,100 |
| Federal tax saved by planning | $9,100 |
A $48k cash balance contribution moves Dr. Sahota back under the joint-filer phase-out ceiling, restoring $38,000 of §199A deduction worth roughly $9,100 in tax. The cash balance contribution also saves another $11,500 in tax. Total savings: about $20,600 from a single coordinated move.
Limits and risks
§199A is scheduled to sunset after 2025, Congress has not yet acted to extend. Planning that depends on this deduction beyond 2025 should be flagged as legislative-risk.
Aggregation elections, once made, must be maintained consistently. Reversing them later is hard.
The 'reputation or skill' subsection of the SSTB definition is the most vague. Service businesses that don't think of themselves as SSTBs sometimes are, and vice versa.
IRS examiners scrutinize aggregation elections and crack-and-pack separations. A clean separation has its own employees, its own customers, its own books, its own real economic substance. A crack-and-pack with shared employees and a back-office contract usually fails.
IRS reference
- IRC §199A20% qualified business income deduction for pass-through owners.
- Treas. Reg. §1.199A-5Definition of specified service trades or businesses (SSTBs).
- Treas. Reg. §1.199A-4Aggregation rules for combining trades or businesses.