The QBI Deduction: A Complete Guide to the 20% Pass-Through Deduction Under Section 199A
The Section 199A deduction can reduce your effective tax rate by up to 20% on pass-through business income. But the rules are layered, and the phase-outs catch more business owners than you would expect.
What the QBI Deduction Is
The Qualified Business Income deduction under IRC Section 199A allows owners of pass-through businesses -- sole proprietorships, partnerships, S-Corps, and certain trusts -- to deduct up to 20% of their qualified business income from taxable income. The OBBBA made it permanent. For business owners earning $200,000 to $500,000 in pass-through income, this deduction saves $15,000 to $35,000 in federal tax per year.
How QBI Is Calculated
QBI is the net amount of qualified items of income, gain, deduction, and loss from a qualified trade or business. Reasonable compensation paid to an S-Corp shareholder-employee reduces QBI. If you have multiple businesses, QBI is calculated separately for each. Losses from one reduce QBI from others, and negative overall QBI carries forward.
The Income Thresholds and Phase-Outs
Below the threshold (~$192K single / ~$384K MFJ in 2026): Full 20% deduction regardless of business type or W-2 wages.
Within the phase-in range ($50K single / $100K MFJ above threshold): W-2 wage and SSTB limitations phase in.
Above the phase-in range: SSTBs receive zero deduction. Non-SSTBs are limited to the greater of 50% of W-2 wages or 25% of W-2 wages plus 2.5% of UBIA of qualified property.
Specified Service Trades or Businesses
SSTBs include health, law, accounting, actuarial science, performing arts, consulting, athletics, financial services, and brokerage. Engineering and architecture are specifically excluded. If your SSTB income exceeds the phase-in range, you get zero QBI deduction -- the cliff that catches doctors, lawyers, and consultants.
Some owners with mixed activities can separate non-SSTB portions into a distinct entity with genuine economic substance and arm's-length pricing.
The W-2 Wage and Property Limitations
For non-SSTBs above the threshold, the deduction is capped at the greater of: (1) 50% of W-2 wages, or (2) 25% of W-2 wages plus 2.5% of UBIA of qualified property. Increasing W-2 wages (including your own S-Corp salary) or retaining depreciable property increases the cap.
Strategies to Maximize the Deduction
Manage taxable income around thresholds via retirement contributions, loss harvesting, or deduction timing. Separate SSTB and non-SSTB activities into distinct entities. Optimize reasonable compensation -- the optimal salary minimizes total tax after FICA, QBI, and retirement effects. Acquire or retain depreciable property to boost the UBIA component. Consider a C-Corp election for SSTB income above the threshold where the 21% rate may beat 37% with no 199A benefit.
Key Takeaways
- The QBI deduction reduces taxable income by up to 20% of qualified business income and is now permanent under the OBBBA.
- Below ~$192K single / ~$384K MFJ, the full 20% applies regardless of business type.
- SSTBs lose the deduction entirely above the phase-in range.
- Above threshold, the deduction is capped by W-2 wages and depreciable property basis.
- The optimal S-Corp salary balances SE tax savings against the QBI deduction.
Frequently Asked Questions
What qualifies as a specified service trade or business?
SSTBs include health, law, accounting, actuarial science, performing arts, consulting, athletics, financial services, and brokerage. Engineering and architecture are specifically excluded.
Can real estate investors claim the QBI deduction?
Yes, if the rental activity rises to the level of a trade or business. The IRS safe harbor under Rev. Proc. 2019-38 allows rentals with 250+ hours of rental services per year to qualify.
Does the QBI deduction reduce self-employment tax?
No. It reduces taxable income only, not AGI or self-employment tax.
What happens if my QBI is negative?
No deduction in the current year. The negative QBI carries forward to reduce QBI from future profitable businesses.
Is the QBI deduction permanent?
Yes. The OBBBA made Section 199A permanent, removing the December 31, 2025 sunset.
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