At a glance
- The threshold fell. For 2026 an excess business loss starts above $256,000 single and $512,000 married filing jointly — down from $313,000 and $626,000 in 2025.
- This is not an indexing quirk. The One Big Beautiful Bill Act made the limitation permanent and reset the threshold to its original 2017 base rather than carrying the 2025 figure forward.
- It is deferral, not disallowance. The excess becomes a net operating loss carryforward. You do not lose it; you lose the year you wanted it in.
- Who it hits. Anyone generating a large business or non-passive rental loss against other income — cost segregation on a short-term rental is the most common trigger.
Two things happened to the loss rules for 2026, and they pull in opposite directions. The first has been covered everywhere: bonus depreciation went back to 100% and became permanent. The second has barely been covered at all, and it quietly takes back part of what the first one gives.
The excess business loss threshold under section 461(l) went down for 2026. Not up with inflation, as it had every year since 2018. Down — by $57,000 for single filers and $114,000 for joint filers.
The 2026 numbers
| Filing status | 2025 threshold | 2026 threshold | Change |
|---|---|---|---|
| Single and all other filers | $313,000 | $256,000 | −$57,000 |
| Married filing jointly | $626,000 | $512,000 | −$114,000 |
The 2026 figures come from Revenue Procedure 2025-32, section 4.31, which states that “the amount under § 461(l)(3)(A)(ii)(II) is $256,000 ($512,000 for joint returns).” The IRS summarised the wider set of 2026 adjustments in its October 2025 release.
What this looks like on an actual return
If you read nothing else, read this. Same taxpayer, same facts, one year apart.
A single filer with $500,000 of wages and $100,000 of dividends and capital gains buys a short-term rental. A cost segregation study and 100% bonus depreciation produce a $400,000 loss, and they materially participate, so the loss is not passive.
| On the return | 2025 rules | 2026 rules |
|---|---|---|
| W-2 wages | $500,000 | $500,000 |
| Dividends and capital gains | $100,000 | $100,000 |
| Loss from the rental | ($400,000) | ($400,000) |
| Threshold — single filer | $313,000 | $256,000 |
| Loss actually allowed this year | ($313,000) | ($256,000) |
| Excess disallowed, carried forward as an NOL | $87,000 | $144,000 |
| Income left to be taxed | $287,000 | $344,000 |
$57,000 more income is taxed in 2026 on identical facts. At a 35% marginal rate that is roughly $20,000 of additional tax in the year you were counting on the deduction. The $144,000 you could not use is not gone — it becomes a net operating loss carryforward — but it arrives in a later year, at whatever rate applies then.
The one-line version. Your loss is capped at the threshold, not at your income. It does not matter that you earned $600,000; a single filer cannot use more than $256,000 of net business loss against it in 2026. Figures here are illustrative and rounded — the arithmetic on a real return depends on the rest of it.
Run your own numbers
The table above uses one set of facts. This does the same arithmetic on yours.
Excess business loss calculator — 2026
Mirrors lines 14 to 16 of Form 461. Enter your income by type and see how much of a business loss actually reaches your return this year.
Income that is not from a trade or business
Trade or business results
Result
What this does and does not do. It applies the section 461(l) threshold to your combined trade or business result and shows the excess, which becomes a net operating loss carryforward. Wages, capital gains and dividends are treated as income from outside a trade or business, so they cannot absorb the loss and only affect what is left to be taxed. It does not perform the Part II adjustment for amounts not attributable to a trade or business, does not compute your actual tax, and does not handle trusts, estates or state conformity. Figures are illustrative. This is general information, not advice for your situation.
Why a threshold went down
This is the part that catches practitioners, because inflation-adjusted figures are not supposed to fall.
The Tax Cuts and Jobs Act introduced the limitation in 2018 with a $250,000 / $500,000 threshold, indexed annually. By 2025 indexation had carried it to $313,000 and $626,000. The One Big Beautiful Bill Act then did two things: it made the limitation permanent, removing the expiry that had been scheduled, and it reset the threshold to the original statutory base rather than continuing to index the 2025 amount forward.
The practical warning. If you or your preparer plan 2026 by taking the 2025 threshold and adding an inflation bump, you will be over by roughly $57,000 or $114,000 — and you will only find out when the return is prepared, which is far too late to do anything about it.
How the limitation actually works
An excess business loss is the amount by which your total deductions from trades or businesses exceed your total gross income and gains from those trades or businesses, plus the threshold. It is computed on Form 461 and it applies to noncorporate taxpayers — individuals, trusts and estates.
Three details do most of the damage in practice, and all three are in the Form 461 instructions.
1. It is the last limitation to apply, not the first
The ordering is fixed: at-risk rules first, then the passive activity loss rules, then section 461(l). That sequence matters because it means clearing the earlier hurdles does not get you home. A short-term rental owner who materially participates has escaped the passive activity rules — and then still meets section 461(l) waiting on the other side.
Most explanations of the short-term rental strategy stop at material participation. That is where the analysis starts, not where it ends.
2. Your W-2 wages are not part of the calculation
This is the subtlety that reverses people’s intuition. The instructions exclude deductions, gross income and gains attributable to the trade or business of performing services as an employee. So your salary is not business income for the purpose of computing the excess.
The consequence is counter-intuitive but important: earning more W-2 income does not raise the amount of business loss you are allowed. The threshold is a fixed ceiling on how much net business loss can reach your other income, whatever that other income happens to be.
3. Disallowed does not mean lost
The excess is treated as a net operating loss carryforward to the following year. Nothing is destroyed. What is destroyed is the timing — and timing was usually the entire point, because these strategies are run to offset a specific year’s income, often a year with a bonus, a liquidity event or an unusually high salary.
A carryforward is worth less than the deduction you planned for. It arrives a year later, it may land in a year with a lower marginal rate, and as an NOL carryforward its use against future income is itself limited. Treating a deferral as if it were a deduction is how a strategy that looked good on a spreadsheet underdelivers in real life.
A worked example: the short-term rental case
This is the fact pattern where the change bites hardest, because 100% bonus depreciation and cost segregation are designed to produce exactly the kind of large first-year loss the limitation targets.
A married couple with $600,000 of combined W-2 income buys a $900,000 short-term rental. A cost segregation study reclassifies $240,000 into five, seven and fifteen-year property. They materially participate, so the loss is not passive, and the average guest stay is under seven days, so it is not a rental activity for passive-loss purposes in the first place. Everything about the structure works.
Say the property produces a net loss of $700,000 after bonus depreciation and operating results.
| Under 2025 rules | Under 2026 rules | |
|---|---|---|
| Net business loss | $700,000 | $700,000 |
| Threshold (MFJ) | $626,000 | $512,000 |
| Loss usable this year | $626,000 | $512,000 |
| Excess carried forward as an NOL | $74,000 | $188,000 |
Same property, same study, same participation. The identical transaction now defers $114,000 more of the deduction into a later year. At a 37% marginal rate, that is roughly $42,000 of tax benefit pushed out of the year it was planned for.
The second case: an operating business
The limitation is not a real estate rule, and business owners are caught by it more often than they expect — usually in a year that already feels bad.
A single-filer consultant has a $400,000 loss from an operating business, funded from savings and from an earlier profitable year. Under 2026 rules, $256,000 offsets other income and $144,000 carries forward. If the reason for the loss was a one-off — a failed product line, a large settlement, a write-off of receivables — the year the relief was actually needed is the year that does not fully get it.
What to do about it
The planning responses are unglamorous and they all have to happen before year end.
Size the study to the threshold, not to the property
A larger cost segregation study is no longer automatically a better one. Where a study would push the loss well past the threshold, the marginal dollars of study fee buy you a carryforward rather than a deduction. That is a materially different purchase, and it should be priced as one.
Consider spreading acquisitions across two tax years
Two properties acquired in consecutive years may produce more usable deduction than two acquired in the same year, because each year gets its own threshold. Where a second purchase is already planned, the closing date is now a tax variable.
Look at what else is on the return
The threshold applies to your net business result. Business income from another source — an S corporation, a profitable partnership interest, a consulting schedule C — absorbs the loss before the threshold is tested, which effectively increases how much of it you can use. Coordinating the two is planning; discovering it in April is not.
Model the carryforward honestly
If a large carryforward is unavoidable, it should be valued at what it is worth in the year it will actually be used, not at this year’s marginal rate. Sometimes that changes whether the transaction makes sense at all.
Where this becomes a real engagement. For anyone planning a purchase, a study, or a large deductible outlay in 2026, the question is no longer “how big a deduction can we generate?” but “how much of it lands this year, and what is the rest worth later?” That is a modeling exercise, and it is worth doing before the money is spent rather than after.
Frequently asked questions
What is the excess business loss threshold for 2026?
$256,000 for single filers and $512,000 for married couples filing jointly, per Revenue Procedure 2025-32. These are down from $313,000 and $626,000 for 2025.
Why did the threshold go down instead of up with inflation?
The One Big Beautiful Bill Act made the section 461(l) limitation permanent and reset the threshold to its original Tax Cuts and Jobs Act base of $250,000 / $500,000, indexed from that base, rather than continuing to index the 2025 figure forward. It is a statutory reset, not an indexing calculation.
Do I lose the disallowed loss permanently?
No. The excess is treated as a net operating loss carryforward to the following year. What you lose is the timing — the deduction arrives in a later year, possibly at a lower marginal rate, and its use is then subject to the NOL rules.
Does my W-2 salary count as business income for this calculation?
No. The Form 461 instructions exclude income and deductions attributable to the trade or business of performing services as an employee. Earning more salary does not increase the amount of business loss you are allowed to use.
Does material participation get me around the limitation?
No, and this is the most common misunderstanding of the short-term rental strategy. Material participation clears the passive activity rules. Section 461(l) is applied afterwards, to whatever loss survives. The ordering is at-risk rules, then passive activity rules, then excess business loss.
Who has to file Form 461?
Noncorporate taxpayers — individuals, trusts and estates — whose net business losses exceed the threshold, and also taxpayers whose losses on any single reporting line exceed half the threshold amount. Check the current-year instructions, as the filing trigger tracks the threshold.
Does the limitation apply at the partnership or S corporation level?
No. It is applied at the owner level. The entity reports its results and each partner or shareholder tests the limitation against their own total business activity and filing status.
Is there a state equivalent?
Some states conform to section 461(l) and some decouple from it entirely, so a loss limited federally may be fully usable at the state level or vice versa. This has to be checked state by state and is one reason a federal-only analysis can mislead.
Related reading
- Short-term rental tax savings calculator — model the cap against your own numbers, on the 2026 rate schedules.
- The STR loophole: how short-term rentals can offset your W-2 income
- 100% bonus depreciation is back — and now permanent
- Material participation for STR owners: the 100-hour rule
- How to qualify for real estate professional status
- Cost segregation for an Airbnb: what it does in year one
Modeling a 2026 purchase or study?
The question is no longer how large a deduction you can generate, but how much of it lands this year. We run that calculation before the money is spent. Thirty minutes, no charge.
This article is general information, not advice for your situation. Thresholds and rules change; figures here are for the 2026 tax year and are sourced to Rev. Proc. 2025-32 and the Form 461 instructions.
