How Section 199A (QBI deduction) affects partnerships, with special attention to Specified Service Trades or Businesses (SSTBs) 

What Is the Section 199A (QBI) Deduction?

• The Qualified Business Income (QBI) deduction, under IRC § 199A, allows non‑corporate taxpayers (like partners in a partnership) to deduct up to 20% of their qualified business income.
  
  

• This benefit applies to partnerships, S corporations, sole proprietorships, trusts, and estates.
  
  

• But: not all business income qualifies — there are limits, especially for Specified Service Trades or Businesses (SSTBs).

How QBI Works for Partnerships

1. Entity-Level vs. Partner-Level

• For 199A purposes, the partnership itself determines whether a trade or business is considered an SSTB.
  
  

• But the limitation on the deduction (phase-out) depends on the partners’ taxable income, not the partnership’s income.
  
  

• Each partner’s Schedule K-1 should report the QBI items, W-2 wages, and unadjusted basis of qualified property (UBIA) so that they can calculate their allowable 199A deduction.
  
  

2. Calculating QBI, W-2 Wages & UBIA

• QBI is the net amount of business income, gains, losses, and deductions from the trade or business.
  
  

• There is a limitation based on W-2 wages paid by the business and the UBIA of qualified property (e.g., real estate, equipment).
  
  

• Partnerships can choose to aggregate multiple trades or businesses for applying these limits, but SSTBs cannot be aggregated with other trades for this purpose.

What Is an SSTB & Why It Matters

• An SSTB is a “Specified Service Trade or Business,” typically involving professions like law, health, accounting, consulting, financial services, etc.
  
  

• For high-income taxpayers, QBI from SSTBs may be completely disallowed once their taxable income exceeds certain thresholds.
  
  

• If a partner in a partnership operates an SSTB, the partner may not get the 199A deduction for that income if their personal taxable income is too high, even if the partnership makes money.

Phase‑out, Thresholds & New OBBBA Changes

• Under current law, there is a threshold and phase-in range for the deduction.
  
  

• For example, in 2024 the joint‑filing threshold is $383,900, and the phase-out goes up to $483,900.
  
  

• Under the OBBBA (recent tax law changes):
  
  

  • The phase-in range for SSTBs is increasing.
    
    

  • A minimum deduction of $400 (adjusted for inflation) may apply for taxpayers with at least $1,000 of QBI.
    
    

  • This ensures even lower‑profit businesses can get some deduction.

Planning Implications for Partnerships With SSTBs

1. Partnership Agreement and Reporting
   
   

   • Partnerships that are or include an SSTB should explicitly report SSTB status on K-1s.
     
     

   • Make sure to track W-2 wages and qualified property basis so each partner can compute their 199A deduction correctly.
     
     

2. Income Management
   
   

   • High‑income partners: consider if their taxable income will push them beyond the SSTB phase-out range.
     
     

   • Use aggregation rules (when allowed) to combine non-SSTB businesses for better 199A planning. But be careful: SSTBs generally can’t be aggregated with non-SSTBs.
     
     

3. Compensation and Wages
   
   

   • Because the 199A deduction is limited by W-2 wages, partnerships might want to adjust how much they pay in wages vs. distributions.
     
     

   • More wages may help maximize the 199A deduction for non-SSTB partners (or partially mitigate limits).
     
     

4. Capital Investments & Property
   
   

   • Investing in qualified property (like real estate, equipment) increases your UBIA, which can help the 199A deduction under the wage/property limit.
     
     

   • For SSTBs, this might make a big difference in how much deduction is allowed for each partner.
     
     

5. Structural Decisions
   
   

   • If part of the partnership business is SSTB and part is not, you might segment them (form separate entities) to maximize the deduction.
     
     

   • Revisit tax projections in light of permanent 199A and new OBBBA thresholds.

Example

Let’s say:

• A law firm partnership (an SSTB) has 3 partners.
  
  

• Each partner’s share of business income is $300,000.
  
  

• Partner A’s total taxable income (before 199A) is $450,000, which is within the SSTB phase‑in range under OBBBA.
  
  

• They each receive $50,000 W-2 wages from the partnership.
  
  

Result:

• Because their income is high but not above the full SSTB cutoff, they may qualify for some portion of the 199A deduction (not full 20%).
  
  

• Their deduction is limited by their W-2 wages and total QBI from the law practice.
  
  

• The partnership should report QBI, W-2 wages, and property basis (if any) on each K‑1 so each can compute their deduction.

Risks & Common Pitfalls

• Overlooking SSTB designation: If a partnership fails to flag that it is an SSTB, partners may miscalculate their deduction.
  
  

• K-1 errors: Poor tracking of W-2 wages or basis of property can lead to under- or over-deduction.
  
  

• Ignoring phase-out rules: Partners whose income crosses the threshold risk losing the deduction entirely.
  
  

• Aggregation mistakes: Trying to aggregate SSTB and non-SSTB businesses incorrectly can lead to IRS issues.

Summary

• The QBI deduction (199A) is a powerful benefit for partnership owners, but SSTBs face special limitations.
  
  

• Under OBBBA, the rules for SSTBs are slightly more generous, thanks to broader phase-in ranges and a minimum deduction.
  
  

• Proper reporting, structuring, and planning are vital to maximizing 199A benefits for partnership owners — especially in professional service firms.

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