QBI Deduction (Section 199A) — Complete Practitioner Guide

What Is the Section 199A QBI Deduction?

The Section 199A Qualified Business Income (QBI) deduction is one of the most significant tax benefits available to owners of pass-through businesses. Enacted as part of the Tax Cuts and Jobs Act (TCJA) in 2017 and made permanent by the One Big Beautiful Bill Act (OBBBA) in 2025, the deduction allows eligible taxpayers to deduct up to 23% of their qualified business income from federal taxable income.

The deduction is available to owners of sole proprietorships, partnerships, S-corporations, and LLCs taxed as pass-throughs. C-corporations do not qualify. The deduction is taken on the individual return (Form 1040, Schedule D equivalent) and reduces taxable income — not adjusted gross income (AGI). Critically, the deduction is available to taxpayers who take the standard deduction as well as those who itemize, making it universally accessible to all pass-through business owners.

Before OBBBA, the §199A deduction was scheduled to expire after December 31, 2025. OBBBA not only made it permanent but also increased the deduction rate from 20% to 23% and widened the income phase-out range, making the deduction more valuable for a broader range of taxpayers going forward.

2026 Income Thresholds and Phase-Out Rules

The QBI deduction is available in full to taxpayers with taxable income below the phase-out threshold. Above the threshold, the deduction is subject to limitations based on W-2 wages and qualified property, and SSTB owners face additional restrictions. The 2026 thresholds are as follows:

Source: IRS Rev. Proc. 2025-40 (2026 inflation adjustments); OBBBA phase-out range widening. Thresholds are based on taxable income, not AGI.

For taxpayers below the lower threshold, the deduction is straightforward: 23% of QBI, limited to 23% of taxable income minus net capital gains. No W-2 wage limitation applies. For taxpayers above the upper threshold, the deduction is limited to the W-2 wage limitation (or eliminated entirely for SSTB owners). For taxpayers in the phase-out range, the limitation is phased in proportionally.

The W-2 Wage Limitation: The Most Important Planning Variable

For taxpayers above the income phase-out threshold, the QBI deduction is limited to the greater of two alternative calculations:

Alternative 1 (W-2 wages only): 50% of the W-2 wages paid by the qualified trade or business during the tax year.

Alternative 2 (W-2 wages + property): 25% of the W-2 wages paid by the qualified trade or business, plus 2.5% of the unadjusted basis immediately after acquisition (UBIA) of all qualified property held by the trade or business at the close of the tax year.

The W-2 wage limitation creates powerful planning opportunities. For service businesses with no significant property (consultants, attorneys, accountants), the only way to increase the W-2 wage component is to pay more wages — either to the owner (via S-Corp election) or to employees. For capital-intensive businesses (real estate, manufacturing), the UBIA component can provide significant additional deduction capacity.

SSTB Rules: Which Professions Are Affected?

A Specified Service Trade or Business (SSTB) is a trade or business in one of the following fields, as defined in IRC §199A(d)(1)(A) and Treas. Reg. §1.199A-5:

Health: Physicians, dentists, nurses, pharmacists, physical therapists, and other healthcare providers performing services in the field of health. Note: veterinarians are NOT SSTBs.

Law: Attorneys, paralegals, and legal professionals performing services in the field of law.

Accounting: CPAs, EAs, bookkeepers, and other accounting professionals. Note: financial advisors are separately classified under financial services.

Actuarial science, performing arts, consulting, athletics, financial services, brokerage services.

Reputation or skill: Any trade or business where the principal asset is the reputation or skill of one or more of its employees or owners. This is the "catch-all" provision and has been the subject of significant IRS guidance and litigation.

For SSTB owners below the phase-out threshold, the SSTB classification has no effect — the full 23% deduction applies. For SSTB owners above the upper phase-out threshold, no QBI deduction is available from the SSTB. For SSTB owners in the phase-out range, the deduction is reduced proportionally.

Stacking the QBI Deduction with the S-Corp Election

The most powerful QBI planning strategy for high-income clients is stacking the §199A deduction with an S-Corp election. The interaction works as follows: an S-Corp owner above the phase-out threshold needs W-2 wages to unlock the QBI deduction. The S-Corp election creates W-2 wages (the reasonable salary) that count toward the W-2 wage limitation. By optimizing the salary level, the practitioner can maximize both the SE tax savings (lower salary = more savings) and the QBI deduction (higher salary = more W-2 wages = higher QBI deduction).

The optimal salary is the point where the marginal SE tax savings from a lower salary are exactly offset by the marginal reduction in the QBI deduction from lower W-2 wages. For most clients, this optimization produces a salary in the range of 40–60% of net profit — which coincidentally aligns with the reasonable salary safe harbor used for audit protection.

Rental Income and the QBI Deduction: The Safe Harbor Rules

Whether rental income qualifies for the QBI deduction depends on whether the rental activity rises to the level of a trade or business. The IRS created a safe harbor in Rev. Proc. 2019-38 for rental activities that meet certain requirements:

Safe harbor requirements: (1) Separate books and records are maintained for the rental activity; (2) 250 or more hours of rental services are performed per year (for activities in existence for fewer than 4 years) or 250 hours per year averaged over the prior 3 years (for activities in existence for 4+ years); (3) the taxpayer maintains contemporaneous records of hours of services performed, description of services, dates, and who performed the services.

Rental activities that do not meet the safe harbor may still qualify for the QBI deduction if they rise to the level of a trade or business under the general facts and circumstances test. Triple-net leases (NNN) are specifically excluded from the safe harbor but may still qualify under the general test.

Self-rentals — where a taxpayer rents property to a business in which they have an ownership interest — are treated as a trade or business for QBI purposes under Treas. Reg. §1.199A-1(b)(14), making them eligible for the QBI deduction without meeting the safe harbor requirements.