You walk into a dealership ready to drop $80,000 on a new piece of equipment. Your accountant says you can deduct the whole thing this year. Great — except now you have to pick which deduction to take. Choose wrong, and you'll either leave money on the table, generate a net operating loss you can't fully use, or trigger a state-level tax surprise that wipes out half the federal benefit.
The One Big Beautiful Bill Act (OBBBA), signed on July 4, 2025, made first-year expensing more generous than it has been in over a decade. Both Section 179 and 100% bonus depreciation are back at full strength — but they are not interchangeable. Each has rules about what qualifies, how much you can deduct, when the election locks in, and how states treat it. The optimal answer depends on the size of your purchase, the type of property, your taxable income, and where you operate.
This guide walks through the new rules, the practical differences, and the strategy small businesses should use in 2026 to maximize legitimate write-offs without creating problems on next year's return.
What OBBBA Actually Changed
For about a decade, the Tax Cuts and Jobs Act made 100% bonus depreciation the default tool for equipment write-offs. That benefit was scheduled to phase out — dropping to 60% in 2024, 40% in 2025, 20% in 2026, and zero by 2027.
OBBBA reversed the slide. The law permanently restored 100% bonus depreciation for qualified property acquired and placed in service after January 19, 2025. There is no longer a sunset date written into the statute.
At the same time, OBBBA expanded Section 179 expensing:
- The maximum deduction jumped from $1 million to $2.5 million (baseline, indexed for inflation).
- The investment phaseout threshold rose from $2.5 million to $4 million.
- For tax years beginning in 2026, inflation-adjusted limits are $2,560,000 for the deduction and $4,090,000 for the phaseout, with the deduction fully phased out at $6,650,000 of qualifying purchases.
A transition election is also available: if you acquired property in 2025 but placed it in service before January 19, you can apply the prior 40% bonus rate (or 60% for certain long-production aircraft).
The Core Differences at a Glance
Before getting into strategy, it helps to see how these two provisions differ on the dimensions that actually matter for planning.
Dollar limit
- Section 179: Capped at $2,560,000 for 2026, with a hard phaseout at $6,650,000 of total qualifying purchases.
- Bonus depreciation: No annual dollar limit. A business buying $20 million of qualifying equipment can deduct the entire $20 million.
Taxable income limitation
- Section 179: Cannot create a loss. The deduction is limited to aggregate business taxable income (including W-2 wages from any trade or business, for individuals). Anything disallowed carries forward.
- Bonus depreciation: Can create or expand a net operating loss. The NOL then carries forward and offsets up to 80% of taxable income in future years.
Election method
- Section 179: Elective on an asset-by-asset basis. You pick which items to expense up to the annual cap.
- Bonus depreciation: Automatic for all qualifying property. To opt out, you must do so by class of property (e.g., all 5-year property), not asset by asset.
Qualified property
- Bonus depreciation: Tangible property with a recovery period of 20 years or less, including used property, certain qualified film and television productions, and qualified improvement property.
- Section 179: Same general property categories, plus certain improvements to nonresidential real property — specifically roofs, HVAC, fire protection, alarm systems, and security systems. These improvements generally don't qualify for bonus depreciation, which makes Section 179 the only first-year option for them.
Recapture rules
- Section 179: Recapture is triggered if business use of the property drops to 50% or less. The previously expensed amount, minus the depreciation that would otherwise have been claimed, is added back to income.
- Bonus depreciation: Standard depreciation recapture rules apply (typically Section 1245 for personal property), generally on disposition.
A Surprise Bonus: Qualified Production Property
OBBBA also created a new Section 168(n) deduction — sometimes called Qualified Production Property (QPP) — that allows 100% expensing of certain non-residential real property used in qualified production activities. This is a genuinely new category, because traditionally buildings are depreciated over 39 years and never qualified for first-year expensing.
To qualify:
- Construction must begin after January 19, 2025, and before January 1, 2029.
- The property must be placed in service before January 1, 2031.
- Original use of the property begins with the taxpayer.
- The structure must be an integral part of manufacturing, agricultural, chemical production, or refining activities.
- Lessors and the office, administrative, or research portions of a facility do not qualify.
There is a sting in the tail: a 10-year recapture rule applies if the property ceases qualifying use early. Stop using a factory as a factory inside that window and you may have to give back the deduction.
If you're contemplating a factory expansion or a new processing facility, this is one of the most significant tax breaks in the bill. It requires careful cost segregation between qualifying production space and disqualified office/admin/research space, but the upfront cash flow benefit is hard to ignore.
How to Choose: A Practical Framework
Here is a five-question framework most small businesses can use without an army of advisors.
1. Will the deduction create or deepen a loss?
If yes, you cannot use Section 179 for the excess — it's capped at taxable income. Bonus depreciation, by contrast, can roll into an NOL.
But "can" doesn't always mean "should." Post-2017 NOLs are limited to offsetting 80% of taxable income in any future year, which can leave value trapped. If your business is unlikely to have meaningful income for several years, accelerating into an NOL may simply defer a deduction you could have spread over the regular depreciation schedule with less waste.
Rule of thumb: If you have plenty of current-year income, Section 179 is fine. If you'd push into NOL territory, model both options before committing.
2. Are you near the Section 179 phaseout?
If your total qualifying purchases will exceed $4,090,000 (for 2026), each additional dollar reduces your Section 179 deduction by a dollar. Above $6,650,000, you can't use Section 179 at all.
Companies near these thresholds typically default to bonus depreciation, which has no phaseout.
3. Are you buying any property that bonus depreciation won't cover?
Roofs, HVAC, fire systems, alarms, and security systems installed in nonresidential property are the classic examples. These qualify for Section 179 but generally not for bonus depreciation.
Same goes for off-the-shelf software in some cases (Section 179 covers it; bonus generally doesn't for the same scope).
4. Do you operate in a state that decouples from federal bonus depreciation?
This is the most overlooked factor. Many states do not conform to federal bonus depreciation, which means you get the full deduction on your federal return but a partial — or no — deduction on your state return.
A few examples:
- California requires a full addback of bonus depreciation. California generally accepts Section 179 expensing, however, making 179 dramatically more attractive at the state level.
- New York does not conform to bonus depreciation and requires an addition modification (with narrow exceptions for property in specific zones).
- Illinois partially conforms but enacted legislation decoupling from Section 168(n) qualified production property for tax years beginning on or after January 1, 2026.
The trend is moving toward more decoupling, not less. In 2017, only 13 states fully decoupled from federal bonus depreciation; today, that number has more than doubled.
Bottom line: A small business operating entirely in a decoupled state often gets more benefit by using Section 179 wherever possible, because state conformity is better. The federal numbers look identical in year one, but the state tax difference can be thousands of dollars per year.
5. Are you buying a vehicle?
Vehicles trigger special rules that override both Section 179 and bonus depreciation:
- Passenger autos (under 6,000 lbs GVWR) are subject to the Section 280F "luxury auto" limits. For 2026, the first-year cap is roughly $12,200, plus an extra $8,000 if bonus depreciation applies — a combined ceiling of about $20,200, regardless of which provision you elect.
- SUVs between 6,001 and 14,000 lbs GVWR have a special Section 179 cap of $32,000 for tax years beginning in 2026 (prorated by business-use percentage). Any remaining basis may then be eligible for bonus depreciation or regular MACRS.
- Heavy trucks and vans with GVWR over 6,000 lbs that are not classified as SUVs (often qualifying as work vehicles) can generally be fully expensed under Section 179 or bonus depreciation, subject to the regular caps.
Buying a $90,000 SUV doesn't get you a $90,000 first-year deduction — it gets you up to $32,000 of Section 179 plus 100% bonus on the remaining $58,000. Get the math wrong here and you'll over-promise the deduction to yourself.
A Worked Example
Suppose you run an S corporation with $600,000 of pre-deduction taxable income. In 2026, you buy:
- A piece of CNC machinery for $400,000 (7-year property)
- A new HVAC system for the shop for $80,000
- A heavy work truck (>6,000 lbs GVWR, not an SUV) for $70,000
Total purchases: $550,000. You're well below the Section 179 phaseout and your taxable income is comfortably above the total deduction.
Strategy: Apply Section 179 to the HVAC system first ($80,000) — bonus depreciation doesn't cover it. Apply Section 179 to the work truck ($70,000) since it's well within limits. Apply 100% bonus depreciation to the CNC machine ($400,000). You're at $0 of federal taxable income from the deduction, while preserving the cleanest treatment for state conformity (in many states, the HVAC and truck pieces will be deductible at the state level, which they would not be under bonus depreciation).
If you'd gone all-in on bonus depreciation, the federal number would be identical — but in California, New York, or another decoupled state, you'd owe noticeably more state tax.
Documentation and Recordkeeping
Accelerated first-year deductions trigger heavier documentation requirements than straight-line depreciation. Practical pointers:
- Maintain a fixed-asset register with placed-in-service dates, acquisition costs, business-use percentages, and elected method (179, bonus, regular).
- Document business-use percentage for any property used personally as well, especially vehicles. The IRS audits this aggressively. Mileage logs, time logs, and contemporaneous notes are far stronger than retroactive estimates.
- Track state adjustments separately. If your state decouples, you'll be carrying a different basis on your state books versus federal books for years. Without a clear state schedule, you risk either double-counting the deduction or missing the future depreciation pickup.
- Keep cost segregation studies if you're claiming Section 168(n) on a production facility. The IRS will scrutinize the split between qualifying production space and disqualified administrative space.
- Be ready to demonstrate "placed in service" dates, not just acquisition dates. Property has to actually be ready and available for its intended use in the year you claim the deduction.
This is exactly where solid bookkeeping makes the difference between a deduction that holds up under audit and one that gets unwound years later with penalties and interest.
Interaction with Other Tax Provisions
Two cross-references worth knowing about:
Section 163(j) interest limitation: Larger deductions reduce taxable income, which reduces the cap on deductible business interest. If your business has substantial interest expense, accelerating depreciation can leave more interest stranded as a carryforward.
Net operating losses: As noted earlier, bonus depreciation can roll into an NOL, but post-2017 NOLs only offset 80% of future taxable income in the year used. Modeling out a few years often surfaces situations where slowing down the deduction yields a better lifetime tax result.
Qualified Business Income (QBI) deduction: Lower taxable income can also reduce the QBI deduction for pass-through owners. Running both calculations side by side is the only way to know which lever produces the better after-tax result.
Common Mistakes to Avoid
- Assuming bonus depreciation is "automatic" means you don't need to plan. It's automatic if you do nothing — but the right answer often involves electing out by class for some property and using Section 179 instead.
- Forgetting that placed-in-service drives timing. A purchase order signed December 30 doesn't get the deduction if the equipment doesn't show up until February.
- Ignoring the SUV cap. The $32,000 ceiling on Section 179 for SUVs catches many small business owners by surprise after they've already taken delivery.
- Skipping the state analysis. A "free" federal deduction can cost you real money if your state requires an addback and you didn't plan for it.
- Stacking deductions you can't use. Generating a giant NOL feels good in the moment, but it locks value into a future year and can complicate Section 163(j), QBI, and state apportionment calculations.
Keep Your Books Audit-Ready From Day One
Accelerated depreciation only saves you money if you can support it on paper — and that starts with clean, ongoing recordkeeping rather than a frantic scramble in April. Plain-text accounting puts every transaction, every fixed asset, and every depreciation schedule into a format you can read, version-control, and reconcile at any time. Beancount.io provides hosted plain-text accounting with transparent data, full audit history, and AI-ready insights — no proprietary file formats, no vendor lock-in. Get started for free and build the kind of financial records that make tax planning easier and audits boring.