QBI Deduction Section 199A:
The 20% Pass-Through Break (2026)
The Qualified Business Income deduction is the most valuable tax break available to most sole proprietors and LLC owners under federal law. The mechanics are messy and the limitations are nuanced. This page walks through the rules clearly enough to know whether your business qualifies and how much it saves.
The 30-Second Version
If your taxable income is below $191,950 single or $383,900 MFJ (2026 thresholds), you can deduct up to 20% of your qualified business income, regardless of what kind of business you run. Above those thresholds, two limitations kick in. First, if your business is a Specified Service Trade or Business (consulting, law, accounting, financial services, healthcare, performing arts, athletics), the deduction phases out and disappears entirely by $241,950 single / $483,900 MFJ. Second, for non-SSTB businesses, the deduction is limited to the greater of 50% of W-2 wages paid or 25% of W-2 wages plus 2.5% of unadjusted basis of qualified depreciable property. The deduction is "below the line" (reduces taxable income, not adjusted gross income) and does not affect SE tax.
What Counts as Qualified Business Income
Qualified Business Income under IRC 199A is the net amount of qualified items of income, gain, deduction, and loss from a qualified trade or business. In plain English: the ordinary business profit of a pass-through entity, with several specific items excluded. The categories of pass-through entities eligible: sole proprietorships (Schedule C), partnerships (Schedule K-1 from a Form 1065), S-Corp shareholders (Schedule K-1 from a Form 1120-S), and certain trusts. Single-member LLCs disregarded for federal tax purposes follow their owner's default classification (typically sole prop / Schedule C).
What is excluded from QBI: reasonable compensation paid by an S-Corp to its shareholder-employee (the W-2 wage portion); guaranteed payments to partners; investment income (interest, dividends, capital gains, real-estate rental from properties classified as investment rather than trade-or-business); income from foreign sources; income from any trade or business of performing services as an employee. The exclusions matter especially for S-Corp owners: the reasonable salary the owner pays themselves is W-2 wages, not QBI, so increasing the salary reduces QBI proportionally and the QBI deduction with it. This creates a planning tension between SE tax savings (which favour low salary, high distribution) and QBI deduction maximisation (which favours higher salary keeping the W-2 wage / UBIA limitations satisfied at high income).
Real estate rental income raises specific questions. Rental real estate is treated as a qualified trade or business for 199A purposes if it rises to the level of a trade or business under general tax law (the "trade or business" test from cases like Groetzinger), or if it meets a safe-harbour test under Rev Proc 2019-38 (250+ hours of rental services per year per enterprise, separate books and records, contemporaneous records). For most small landlords with one or two rental properties, meeting the safe harbour requires deliberate effort; many small landlords end up outside QBI treatment.
The Specified Service Trade or Business Limitation
IRC 199A defines Specified Service Trade or Business (SSTB) to include trades or businesses involving the performance of services in the fields of health, law, accounting, actuarial science, performing arts, consulting, athletics, financial services, brokerage services, and any trade or business where the principal asset is the reputation or skill of one or more employees or owners. Treasury Regulation 1.199A-5 details the specific definitions and exceptions, including a "trickier" category for situations where a business has both SSTB and non-SSTB components.
The SSTB designation matters only above the lower income threshold ($191,950 single / $383,900 MFJ for 2026). Below the threshold, an SSTB owner gets the full 20% QBI deduction just like any other business. In the phase-out range between the lower and upper thresholds, the QBI deduction phases out proportionally to zero. Above the upper threshold, an SSTB owner gets no QBI deduction at all.
For non-SSTB businesses above the lower threshold, a different limitation applies: the deduction is limited to the greater of 50% of W-2 wages paid by the qualified trade or business or 25% of W-2 wages plus 2.5% of unadjusted basis immediately after acquisition (UBIA) of qualified depreciable property. This is the "W-2 wage and UBIA limitation". It exists to channel the deduction toward businesses that genuinely employ workers and invest in capital, not toward high-income passive structures. For a sole proprietor with no employees, the W-2 wages limit at zero, meaning the deduction is limited to 2.5% x UBIA, often a meaningful constraint for higher-income sole props.
Computing the Deduction at Three Income Levels
Three illustrative examples assuming single filer, standard deduction taken, no other complications:
Example 1: $80K consulting net profit (single)
Taxable income (after standard deduction and one-half SE tax deduction) approximately $69,000. Well below the $191,950 lower threshold, so SSTB status does not matter. QBI deduction is 20% of $80K = $16,000. The deduction reduces taxable income to roughly $53,000. Federal income tax at 22%/12% blended marginal saves about $2,400 - $3,200 compared to no QBI. Plain win.
Example 2: $220K consulting net profit (single, SSTB)
Taxable income approximately $205,000, between the lower threshold ($191,950) and upper threshold ($241,950). SSTB phase-out applies. The QBI deduction is partial: the deduction is reduced by a ratio of (taxable income over the lower threshold) / ($50,000 phase-out range), or about $13,050 / $50,000 = 26.1% phase-out. Full deduction would be 20% of $220K = $44,000; phased-out deduction is roughly $44,000 x (1 - 0.261) = $32,520. Federal income tax saving on the deduction at 32% marginal is roughly $10,400.
Example 3: $400K consulting net profit (single, SSTB)
Taxable income well above the $241,950 upper threshold. SSTB owners get zero QBI deduction. The planning shifts to retirement contributions, defined benefit plans, and other structural adjustments. Forming a multi-entity structure to separate SSTB activities from non-SSTB activities is sometimes considered but the IRS has anti-abuse regs limiting bright-line workarounds.
The S-Corp Interaction: Salary vs QBI Trade-off
For an LLC member who has elected S-Corp tax treatment, the QBI computation includes only the pass-through K-1 income, not the W-2 wages paid to the shareholder-employee. This creates a planning tension: paying a higher W-2 salary reduces SE tax savings (because more income is subject to FICA), but it also reduces QBI (because the wages are not QBI). Conversely, paying a lower W-2 salary increases SE tax savings but also increases QBI subject to the W-2 wage limitation at high income.
The optimal salary level depends on whether you are below or above the W-2 wage limitation threshold. Below the threshold (most small S-Corp owners), the QBI deduction is full regardless of W-2 wages, so the salary level only affects SE tax. Above the threshold, the QBI deduction is limited by 50% of W-2 wages, so higher salary may unlock more QBI deduction even at the cost of more FICA. The math is income-band specific and warrants tax-professional input above the lower threshold. Below the threshold, the standard advice (set a defensible market-rate salary, distribute the rest) generally remains optimal.
Aggregation Election
For taxpayers with multiple pass-through businesses, the QBI computation can be done separately for each business or aggregated under specific rules in Treasury Regulation 1.199A-4. Aggregation can be advantageous when one business has positive QBI and high W-2 wages while another has positive QBI but low W-2 wages; combining them lets the high-wage business's W-2 limitation cover the low-wage business's QBI.
The aggregation rules are technical: the businesses must satisfy a 50% common ownership test, must be in the same kind of business (or share a significant operational connection), and the aggregation election must be consistent across years once made. For investors with multiple rental properties or multiple sole prop businesses, the aggregation analysis is often beneficial and is worth running through annually. For single-business owners the aggregation election does not apply.
The Post-TCJA Extension Question
The Section 199A deduction was originally enacted by the Tax Cuts and Jobs Act with a scheduled sunset at the end of 2025. Many of the TCJA individual provisions were also scheduled to sunset. The One Big Beautiful Bill Act passed in 2025 extended Section 199A and many TCJA provisions with modifications. Specific terms continue to be the subject of legislative refinement and IRS guidance development.
For planning purposes, sole props and LLC owners should assume the deduction remains available in its broadly current form for the near future but should not commit to long-term structures that depend on QBI continuing unchanged. The thresholds, the SSTB definitions, the W-2 wage and UBIA limitations, and the percentage of deduction are all subject to potential future revision. Annual review of QBI structure with a tax CPA is appropriate for owners whose income approaches or exceeds the phase-out thresholds.