Home Questions Amending a return for a missed QBI deduction
Tuesday • Asked by a Richardson business owner
My current CPA missed the QBI deduction last year. Can I amend, and is it worth it?
A full answer from Michael R. Cowell, CPA, EA, CFE. The kind of question that comes up on a first call, written out the way I would explain it.
The short answer
Yes. You can generally amend a return for up to three years from the original filing date, and a missed qualified business income deduction is one of the more common reasons to do it. Whether it is worth it is simple arithmetic: the deduction can be up to 20 percent of qualified business income, so the refund is often well worth the cost of the amendment.
The amendment window
An individual return is amended on Form 1040-X. The deadline to claim a refund is generally three years from the date the original return was filed, or two years from the date you paid the tax, whichever is later. A return filed last spring is comfortably inside that window.
If the year in question is still open under that rule, a deduction the original preparer missed can be claimed now.
What the QBI deduction is
The qualified business income deduction, from Section 199A, lets owners of pass-through businesses, such as sole proprietorships, partnerships, and S-corps, deduct up to 20 percent of their qualified business income. It is taken on the return itself and does not reduce self-employment tax, but against income tax it is a substantial deduction that requires no spending to earn.
Why preparers miss it
The headline is simple, but the mechanics are not. Above an income threshold the deduction is limited by W-2 wages the business paid and by the cost of its qualified property, and certain service businesses face an additional phaseout. There is also an option to aggregate related businesses. A return prepared quickly, or by someone who treats the business income as an afterthought, can skip the calculation entirely or stop at the first limit instead of working it through.
Deciding whether it is worth it
The math is direct. The refund is roughly your marginal tax rate multiplied by the deduction you were entitled to. A business owner with meaningful qualified income is usually looking at a refund well into four figures, often more. Set against the cost of preparing one amended return, the decision is almost always clear. The only real friction is gathering the prior-year detail, which is a few hours of work, not a project.
What to do
- Pull the originally filed return and the underlying business income figures.
- Confirm the business income qualifies and identify which limits, if any, apply.
- Recompute the deduction and the corrected tax.
- File Form 1040-X, and amend the state return too if the state conformed to the deduction.
This is general guidance, not advice for your specific situation, and it is current as of when it was written. Tax law changes and the right answer depends on your full picture. That is what the first call is for.
Keep reading
Other questions clients ask.
Your situation, not the general case
This answer is the shape of the problem. Your numbers are the rest of it.
If this is close to something you are dealing with, the first call is free and we work from your actual situation.