QBI Deduction Optimizer — Section 199A (2026)

How the Section 199A phase-out works in 2026

The 23% QBI deduction is tested against your taxable income (not gross income). Three zones:¹

• Below threshold: full 23% deduction, no W-2 wage requirement, no limitation at all.
• Phase-out zone: For non-SSTBs, the deduction phases from uncapped toward the W-2/property limit. For SSTBs, the deductible income itself phases toward zero.
• Above phase-out: SSTBs get $0. Non-SSTBs are limited to the greater of 50% of W-2 wages or 25% of W-2 wages + 2.5% of qualified property cost basis.

What counts as an SSTB?

Specified Service Trades or Businesses (§ 199A(d)) are fields where the principal asset is the skill or reputation of employees or owners:³

• Health — physicians, dentists, veterinarians, nurses, therapists
• Law
• Accounting and actuarial science
• Consulting (broadly defined by IRS regulations — Reg. § 1.199A-5(b)(2)(vii))
• Financial services and brokerage
• Performing arts and athletics

Technology, software, product businesses, real estate, manufacturing, and retail are not SSTBs and retain the W-2-limited deduction above the threshold if they pay W-2 wages.

The Solo 401(k) lever

Every dollar contributed to a Solo 401(k), SEP-IRA, or cash balance plan reduces your taxable income — moving you lower in the phase-out zone.

Example: A management consultant filing single with $255,000 in net income is $53,225 into the phase-out zone. Her current QBI deduction is about $35,800 — not the full $58,650 she'd get below the threshold. By contributing $24,500 to a Solo 401(k) employee deferral + $28,725 as an employer contribution (20% of net SE income), she gets her taxable income to $201,775 exactly, recovers the full 23% deduction worth $58,650, and saves an additional ~$7,300 in federal taxes — on top of the retirement account growth benefit.

2026 Solo 401(k) limits: $24,500 employee deferral ($32,500 at age 50+; $35,750 at ages 60–63 via super catch-up), plus an employer contribution up to 25% of W-2 wages (S-corp) or 20% of net SE income (sole prop), combined limit $72,000.⁴

Why the W-2 wage limitation matters for S-corps above the threshold

If your taxable income exceeds $276,775 (single) / $553,500 (MFJ) and you're not an SSTB, you can still claim a deduction — limited to the greater of:

• 50% of your W-2 wages paid to employees (including your own S-corp officer salary), or
• 25% of W-2 wages + 2.5% of the unadjusted cost basis of qualified depreciable property

An S-corp owner paying herself $120,000 in salary above the threshold can still claim up to $60,000 in QBI deduction (50% × $120K) — a major reason high-income S-corp owners should not set salary too low.

Sources

1. IRS — 2026 Tax Inflation Adjustments (OBBBA amendments). Phase-out thresholds: $201,775 single / $403,500 MFJ for tax year 2026.
2. Tax Foundation — Section 199A and the One Big Beautiful Bill. 23% rate, expanded $75K/$150K phase-out range, $400 minimum deduction.
3. IRC § 199A — Qualified Business Income Deduction (Cornell Law). SSTB definitions (§ 199A(d)) and W-2 wage / property limitation.
4. IRS — Solo 401(k) / One-Participant 401(k) Plans. 2026 contribution limits: $24,500 employee deferral, $8,000 catch-up (50+), $11,250 super catch-up (60–63), $72,000 combined limit.

Section 199A values verified against IRS 2026 inflation adjustments (IRS newsroom, OBBBA amendments) and Tax Foundation analysis of the One Big Beautiful Bill Act (enacted July 2025). Deduction rate 23%, phase-out thresholds $201,775/$403,500, range $75K/$150K.