QBI Deduction: Definition and How It Works

The Qualified Business Income (QBI) deduction — formally established under IRC §199A — allows eligible owners of pass-through businesses to deduct up to 20% of their net qualified business income from taxable income, reducing the effective top marginal rate on pass-through income from 37% to 29.6%. Originally enacted by the Tax Cuts and Jobs Act of 2017 (TCJA, Pub. L. 115-97), the deduction was scheduled to expire after 2025. The One Big Beautiful Bill Act (OBBBA) made it permanent. The deduction is claimed on Form 8995 (simpler situations) or Form 8995-A (higher-income filers subject to limitations) and does not reduce self-employment income for SE tax purposes.

How the Deduction Is Calculated

For most taxpayers below the income phase-out thresholds, the QBI deduction is 20% of net qualified business income — straightforward to apply. The phase-out thresholds (before OBBBA inflation adjustments) are $197,300 for single filers and $394,600 for married filing jointly. Consult the current-year Form 8995-A instructions and IRS Publication 535 for the thresholds as adjusted under OBBBA.

Above the phase-out threshold, two limitations can reduce or eliminate the deduction:

W-2 Wage Limitation. The deduction cannot exceed the greater of (a) 50% of W-2 wages paid by the qualifying business, or (b) 25% of W-2 wages plus 2.5% of the unadjusted basis of qualified depreciable property. This limitation rewards S-Corp owners who pay a reasonable W-2 salary — the wage base created by that salary can unlock a larger QBI deduction at high income levels.

Specified Service Trade or Business (SSTB) Exclusion. Businesses in law, health, consulting, financial services, accounting, athletics, and certain other professional service fields are phased out of the QBI deduction as owner income rises through the threshold. Above the upper limit of the phase-out range, SSTB owners receive zero deduction regardless of wages or property. Below the phase-out range, SSTBs qualify in full.

Examples

Below the phase-out — non-SSTB LLC: A general contractor operating as a sole proprietorship earns $140,000 in net income. QBI deduction: $28,000 (20% × $140,000). The W-2 wage limitation does not apply at this income level.

Above the phase-out — S-Corp, W-2 wage planning matters: An S-Corp owner earning $450,000 in net income from a manufacturing business (non-SSTB) is subject to the W-2 wage limitation. If the corporation pays $120,000 in wages, the W-2 test allows up to $60,000 (50% × $120,000) as the deduction cap — more than 20% of QBI would otherwise require. Proper salary structuring ensures the full deduction is preserved.

Above the phase-out — SSTB: A solo attorney or CPA practice above the upper phase-out boundary receives a $0 QBI deduction. The entity structure (LLC vs S-Corp) does not change this result; SSTB status eliminates the deduction entirely at that income level.

How CPAs Use This in Practice

The QBI deduction is one of the primary drivers behind S-Corp election analysis. An S-Corp owner in a non-SSTB business can simultaneously reduce self-employment tax through distributions and satisfy the W-2 wage test by paying a defensible reasonable salary — maximizing both benefits at once. The interaction between reasonable salary level, W-2 wages, and the §199A limitation requires annual modeling, particularly when income is rising through the phase-out range.

For a complete methodology covering SSTB classification, income thresholds, Form 8995-A mechanics, and the salary-and-wages optimization strategy, see QBI Deduction in 2025: How Section 199A Works After OBBBA. For how the QBI deduction interacts with entity selection, see S-Corp vs LLC: Which Tax Structure Saves More in 2025? and C-Corp vs S-Corp vs LLC: The Complete Entity Selection Guide for CPAs. For reasonable salary documentation — the W-2 base the W-2 wage limitation depends on — see How to Calculate and Document a Reasonable S-Corp Salary.

Related Terms

  • Pass-Through Entity — A business taxed at the owner level rather than the entity level (sole proprietorship, partnership, LLC, or S-Corp). All pass-through entities are potentially eligible for the QBI deduction; C-Corporations are not. States have enacted pass-through entity tax (PTET) elections that shift state tax to the entity level, which also reduces QBI.
  • S-Corporation — A pass-through entity taxed under Subchapter S. S-Corp owner-employees receive W-2 wages that form the base for the W-2 wage limitation calculation — making salary structuring a central QBI planning tool.
  • Section 199A — The IRC provision establishing the QBI deduction. Often used interchangeably with "QBI deduction."
  • Specified Service Trade or Business (SSTB) — A professional service business category (law, health, consulting, financial services, accounting) subject to the QBI phase-out at higher income levels. SSTB status eliminates the deduction entirely above the upper phase-out boundary.
  • W-2 Wage Limitation — The high-income cap on the QBI deduction, calculated from wages paid by the qualifying business. For S-Corp owners subject to this limitation, reasonable salary decisions directly affect the maximum allowable deduction.