The QBI Deduction With Two Businesses: Why Your 20% Might Already Be Gone

“How does the QBI deduction work with two active businesses — one Schedule C with a net profit and one with a net loss? Is QBI only possible if the combined total is a profit?”

The QBI deduction looks simple — 20% off your pass-through profit — until you own two businesses and one of them loses money.

Quick answer: The QBI deduction nets everything. All your qualified pass-through activity — Schedule Cs, partnerships, S-Corps and qualifying rentals — combines into one number before the 20% is figured. If the total is negative, there’s no deduction this year, and the loss carries forward to reduce future QBI. With QBI now permanent, know your carryforward before you count on the 20%.

The QBI deduction in 60 seconds

The qualified business income (QBI) deduction is often described as a gift: up to 20% of the net income from pass-through businesses — sole proprietorships on Schedule C, partnerships, S-Corps, farms and qualifying rental activity. C-Corps don’t get it. There are ceilings: depending on your income and the type of business, the deduction can be limited or phased out entirely.

The netting rule: everything combines

Here’s the surprise. QBI isn’t figured business by business in isolation. Your profitable Schedule C and your losing Schedule C — plus your partnerships, S-Corps and qualifying rentals — are combined into one QBI number first. So yes, the deduction effectively depends on the combined total being a profit.

Negative QBI carries forward

It gets worse: negative QBI doesn’t just cancel this year’s deduction — it carries forward. Laura has seen clients, often with real estate, carrying millions of dollars of negative QBI year after year. Then a profitable business finally shows up, they’re counting on that 20% — and the old losses have to be used up first. The deduction they planned for is already gone.

The QBI deduction is permanent now — track your number

The 2025 tax law made the QBI deduction permanent, so it’s worth planning around rather than hoping for. Put “QBI carryforward” on your planning checklist: ask your preparer for your qualified business loss carryforward (it appears on Form 8995 or 8995-A), and factor it in before you project what a profitable year will save you.

Official IRS reference: IRS — Qualified Business Income Deduction

Key takeaways

• The QBI deduction is up to 20% of net pass-through income — C-Corps don’t qualify.
• All your qualified businesses and rentals are netted into one QBI number.
• If the combined total is negative, there’s no deduction this year.
• Negative QBI carries forward and must be absorbed before future deductions.
• QBI is now permanent — know your carryforward before counting on the 20%.

QBI Deduction FAQs

Related questions from this Q&A

• S-Corp made an extra $70K? Start with reasonable compensation
• Should you use an S-Corp for rental property?

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Disclaimer: This article is for educational purposes only and is not tax, legal, or financial advice. Every situation is different — talk to a qualified professional about your specific facts before making any decisions.