QBI Deduction (IRC 199A): SSTB Rules, W-2/Property Tests, and How to Maximize the 20% Pass-Through Deduction

By Yarik Yarosh, CPA ·September 5, 2026 ·7 min read

Written by Yarik Yarosh, CPA (US & Canada) September 5, 2026 · FL CPA license AC61704 · CPA Ontario

The qualified business income (QBI) deduction under IRC 199A, made permanent by the OBBBA, allows eligible taxpayers to deduct up to 20% of their qualified business income from pass-through entities. For a business owner in the 37% bracket, the effective top rate on pass-through income drops to 29.6% (37% x (1 - 20%)), making it competitive with the 21% corporate rate when considering the absence of double taxation. The deduction is available to sole proprietors, S-Corp shareholders, partners, and LLC members. The complexity comes from three layers of limitations: (1) the overall cap of 20% of QBI, (2) the W-2 wage and qualified property tests for higher-income non-SSTB businesses, and (3) the phase-out and complete elimination for specified service trades or businesses (SSTBs) above the income thresholds.

✓Key takeaway

QBI deduction basics (2025):

Element	Details
Maximum deduction	20% of qualified business income
Available to	Sole proprietors, S-Corp shareholders, partners, LLC members
NOT available to	C-Corporation shareholders, employees (W-2 income isn’t QBI)
Overall cap	Lesser of: (a) 20% of QBI, or (b) 20% of taxable income minus net capital gain
OBBBA status	Permanent (no longer set to expire)

Income thresholds (2025):

Filing Status	Full Deduction Below	Phase-Out Range	No SSTB Deduction Above
Single	$197,300	$197,300 - $266,950	$266,950
MFJ	$394,600	$394,600 - $533,900	$533,900

Below the threshold: Full 20% deduction, no W-2/property test, SSTB classification irrelevant.

Above the threshold (non-SSTB): Deduction limited to the GREATER of:

Test	Formula
W-2 wage test	50% of W-2 wages paid by the business
W-2 + property test	25% of W-2 wages + 2.5% of unadjusted basis of qualified property (UBIA)

Above the threshold (SSTB): Deduction phases out completely, reaching $0 above the upper threshold.

Specified service trades or businesses (SSTBs):

SSTB (Deduction Phases Out)	NOT SSTB (W-2/Property Test Applies)
Health (doctors, dentists, veterinarians)	Architecture
Law	Engineering
Accounting	Real estate (brokerage, property management, development)
Actuarial science	Construction
Performing arts	Manufacturing
Consulting	Retail
Athletics	Wholesale
Financial services	Restaurants
Brokerage services	Technology (product companies, not consulting)
Any trade where the principal asset is the reputation or skill of employees	Farming/agriculture

How do QBI calculations work at each level?

Hypothetical example

Round numbers. Three business owners. All S-Corps. Comparing QBI outcomes.

Owner 1: Below the threshold (taxable income $150,000) A dentist (SSTB). S-Corp. Net income after reasonable salary: $150,000 QBI.

Calculation	Amount
QBI	$150,000
20% of QBI	$30,000
SSTB classification	Irrelevant (below threshold)
W-2/property test	Not required (below threshold)
QBI deduction	$30,000
Tax savings (24% bracket)	$7,200

Below the threshold, even SSTBs get the full 20% deduction. SSTB classification only matters above $197,300 (single) / $394,600 (MFJ).

Owner 2: Above the threshold (non-SSTB, taxable income $500,000) A construction company owner (non-SSTB). S-Corp. QBI: $400,000 after $200,000 reasonable salary. W-2 wages paid (including owner): $500,000. UBIA of qualified property (equipment, vehicles): $800,000.

Test	Calculation	Limit
20% of QBI	$400,000 x 20%	$80,000
W-2 wage test	$500,000 x 50%	$250,000
W-2 + property test	($500,000 x 25%) + ($800,000 x 2.5%)	$125,000 + $20,000 = $145,000

Deduction	Lesser of 20% QBI and GREATER of the two tests
20% of QBI	$80,000
Greater of W-2 tests	$250,000 (W-2 wage test wins)
QBI deduction	$80,000 (limited by 20% of QBI, not by the W-2 test)
Tax savings (35% bracket)	$28,000

This non-SSTB owner gets the full $80,000 deduction because the W-2 wage test ($250,000) far exceeds the 20% QBI cap ($80,000). The deduction is effectively unlimited by the W-2/property test.

Owner 3: Above the threshold (SSTB, taxable income $500,000 MFJ) A law firm partner (SSTB). Taxable income: $500,000 (MFJ). QBI from law firm: $350,000.

Phase-out calculation	Amount
MFJ threshold	$394,600
Phase-out range	$394,600 - $533,900 ($139,300 range)
Taxable income	$500,000
Amount into phase-out	$500,000 - $394,600 = $105,400
Phase-out percentage	$105,400 / $139,300 = 75.7% phased out
Applicable percentage	100% - 75.7% = 24.3%
QBI included	$350,000 x 24.3% = $85,050
20% of included QBI	$85,050 x 20% = $17,010
QBI deduction	$17,010
Tax savings (35% bracket)	$5,954

If this partner’s taxable income exceeded $533,900, the QBI deduction would be $0.

Strategies to maximize QBI deduction:

Strategy	How It Works	Best For
Stay below the SSTB threshold	Time income, maximize deductions, contribute to retirement plans	SSTB owners near the threshold
Increase W-2 wages	Higher wages = higher W-2 test cap (but wages aren’t QBI)	Non-SSTB above threshold with low W-2 payroll
Acquire qualified property	UBIA increases the W-2 + property test	Capital-intensive non-SSTB businesses
Aggregate related businesses	Reg. 1.199A-4 allows aggregating related trades for the W-2/property test	Owners with multiple entities
Split SSTB from non-SSTB activities	If a business has both SSTB and non-SSTB operations, properly separating them preserves the deduction on the non-SSTB portion	Mixed-activity businesses
S-Corp salary reduction (careful)	Lower salary = more QBI (but must meet reasonable comp)	S-Corp owners
Charitable giving (reduce taxable income)	Can bring taxable income below the SSTB threshold	SSTB owners just above threshold

SSTB threshold management example: An accountant (SSTB) with $420,000 projected MFJ taxable income. The QBI deduction is partially phased out.

Strategy	Taxable Income	QBI Deduction	Tax Savings
No planning	$420,000	~$12,000 (partially phased out)	$4,200
Solo 401(k) contribution ($70,000)	$350,000	$35,000 (full 20%, below threshold)	$12,250
401(k) + HSA ($8,550) + home office deduction ($5,000)	$336,450	$35,000 (full 20%)	$12,250

The $70,000 solo 401(k) contribution costs nothing (it’s retirement savings, not spending) but increases the QBI deduction from $12,000 to $35,000, saving an additional $8,050 in taxes.

Illustrative numbers only, not a real client and not advice for your facts.

Related guides:

How do specified service trades or businesses affect your QBI deduction?

Specified service trades or businesses (SSTBs) including law, medicine, accounting, consulting, financial services, and performing arts face a phase-out of the QBI deduction at higher income levels. For 2025, the QBI deduction phases out for SSTBs between $191,950 and $241,950 for single filers and $383,900 and $483,900 for joint filers, with zero deduction above the upper threshold. Non-SSTB businesses above the income threshold are limited to the greater of 50% of W-2 wages or 25% of W-2 wages plus 2.5% of the unadjusted basis of qualified property, but they never lose the deduction entirely. The SSTB classification looks at the principal asset of the business, so if more than 10% of gross receipts come from specified service activities (5% for businesses with over $25 million in gross receipts), the entire business is treated as an SSTB.

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Cite this page

Yarik Yarosh, CPA. "QBI Deduction (IRC 199A): SSTB Rules, W-2/Property Tests, and How to Maximize the 20% Pass-Through Deduction." Blue Cloud CPA, September 5, 2026. https://bluecloudcpa.com/guides/small-business-qbi-deduction-irc-199a-sstb-rules-2025

This guide is general information, not tax advice for your specific situation. Which points apply, and how, depends on your facts.