If you have been postponing a forklift purchase, a kitchen build-out, or a server refresh because the 2025 depreciation rules looked uninspiring, take another look at your calendar. The One Big Beautiful Bill Act made a quiet but consequential change for small business owners: 100% bonus depreciation under Section 168(k) is back, and this time it is permanent. Any qualified property acquired and placed in service after January 19, 2025 can be written off entirely in the first year, instead of being squeezed through the old phase-down that would have dropped the rate to 40% in 2025 and zero by 2027.
For owners who plan capital expenditures with one eye on the tax code, this is a structural change rather than a one-year giveaway. It also brings a few new wrinkles: a fresh Section 168(n) deduction for manufacturing facilities, a higher Section 179 ceiling, and a binding-contract acquisition rule that punishes sloppy paperwork. The remainder of this guide walks through what the new regime looks like in practice, how to think about timing, and how to keep your books clean enough to actually capture the benefit.
What the Statute Actually Says
Section 168(k) has, in some form, existed since 2002. Under the prior law that came out of the Tax Cuts and Jobs Act, the deduction was scheduled to phase down by 20 points each year, reaching 40% for property placed in service in 2025, 20% in 2026, and zero in 2027. That schedule is now gone.
The new rules can be summarized in five points:
- Rate: 100% permanent. Qualified property gets a full first-year write-off with no future sunset built in.
- Effective date: after January 19, 2025. Property acquired and placed in service after that date qualifies. Property still under written binding contracts entered into on or before that date generally remains on the old phase-down schedule.
- Property class: 20 years or less. The traditional rule still applies. This sweeps in most machinery, equipment, vehicles, computers, off-the-shelf software, and qualified improvement property (QIP).
- Used property is fine. As under the post-2017 framework, qualified used property continues to qualify, provided it was not previously used by the taxpayer or a related party.
- Election to opt down. For the first tax year ending after January 19, 2025, taxpayers may elect the old TCJA 40% rate (60% for long-production-period property) instead of 100%. This is useful in narrow circumstances — for example, when net operating losses would otherwise be wasted at a low marginal rate.
The IRS published interim guidance in Notice 2026-11 confirming that most of the familiar regulations from the previous bonus depreciation era — including the binding-contract acquisition rules and the qualified used property tests — will carry forward with only minor adjustments.
Why the Acquisition Date Matters More Than You Think
Throughout the prior phase-down period, taxpayers learned to argue about a single sentence: when was the property actually acquired? The same fight is back, now with the opposite incentive. You want to be on the post-January-19, 2025 side of the line, not the pre-side.
The rule of thumb is straightforward. If you bought equipment off the showroom floor on March 1, 2026 and started using it the same day, both the acquisition and placed-in-service dates are March 1, 2026, and you qualify. If you signed a written binding contract on December 1, 2024 for custom-built equipment that did not arrive until April 2026, your acquisition date is December 1, 2024, and you are stuck on the 40% rate even though placed-in-service is in 2026.
A "written binding contract" is a contract enforceable under state law against the taxpayer that does not limit damages to a specified amount. Liquidated-damages clauses below 5% of the contract price disqualify a contract from being binding for this purpose. The acquisition date is then the later of: the contract date, the date it became enforceable under state law, the end of any cancellation period, or the date all contingencies were satisfied.
In plain terms: small business owners who custom-order heavy equipment, vehicles, or specialty fixtures should review draft purchase agreements with their accountant before signing. Renegotiating a contract with a low liquidated-damages cap can sometimes preserve eligibility for 100% bonus depreciation.
How Section 179 Fits In
Section 179 expensing did not disappear. The OBBBA also raised its ceiling. For tax years beginning in 2026:
- Section 179 maximum deduction: $2.56 million
- Phase-out threshold: begins at $4.09 million in qualifying purchases
- Full phase-out: at $6.65 million
These figures are now indexed annually for inflation.
The two regimes interact in a specific order. The mechanics of a return require Section 179 first, bonus depreciation second, and ordinary MACRS depreciation third. In a typical year a business will:
- Elect Section 179 expensing on whichever assets it most wants to write off — often shorter-lived equipment or the items most likely to be sold or scrapped soonest.
- Apply 100% bonus depreciation under Section 168(k) to any remaining qualifying basis.
- Depreciate any leftover non-qualifying basis on the normal MACRS schedule.
So why bother with Section 179 at all if bonus depreciation is back to 100%? Because the two tools have meaningfully different personalities:
- Section 179 cannot create a loss. It is capped at your taxable business income. Bonus depreciation can create or deepen a net operating loss, which you can then carry forward.
- Section 179 lets you pick and choose by asset and by dollar amount. Bonus depreciation is generally all-or-nothing within a property class. You can elect out of bonus depreciation, but the election applies to an entire class of property for the year.
- State conformity differs. Many states conform partially or selectively to federal depreciation rules. Some conform to Section 179 but not to bonus depreciation, or vice versa. Knowing how your state treats each regime can be worth real money.
- Section 179 has narrower property scope. It covers tangible personal property plus a defined set of nonresidential real-property improvements (roofs, HVAC, fire protection, alarm and security systems). Bonus depreciation also reaches Qualified Improvement Property, which expands the universe of write-offs for tenants doing build-outs.
A small manufacturer that purchases $4.5 million of qualifying equipment in 2026 sits just above the Section 179 phase-out threshold. With $410,000 of phase-out reducing the Section 179 cap to roughly $2.15 million, the company would typically expense $2.15 million under 179 and then claim 100% bonus depreciation on the remaining $2.35 million. The same $4.5 million purchase could also be written off entirely through Section 168(k) alone — but only if the state's conformity rules and the firm's loss posture make that a better answer than the hybrid approach.
Qualified Improvement Property: The Sleeper Provision
QIP is one of those tax terms that does more work than its name suggests. It refers to any improvement made by the taxpayer to the interior of nonresidential real property after the building was first placed in service. Enlargements of the building, elevators and escalators, and structural framework do not count.
Because QIP has a 15-year recovery period — well within the 20-year ceiling for bonus depreciation — interior build-outs at offices, warehouses, retail spaces, and restaurants are now eligible for full first-year expensing as long as the work was placed in service after January 19, 2025.
This is a big deal for tenant-improvement-heavy businesses. A coffee shop that spent $180,000 over the past year on a new HVAC system, refrigeration upgrades, custom millwork inside its leased space, and decorative lighting can now front-load the entire deduction rather than spreading it over fifteen years. The catch is documentation: you need invoices itemizing work to the level of detail that lets you separate interior-improvement spend from structural enlargements, exterior improvements, or land-related costs. Sloppy general-contractor invoices that lump everything together are the most common reason QIP claims get partially disallowed on examination.
The New Section 168(n) Election for Manufacturers
A separate provision in the same act created an entirely new deduction under Section 168(n). For nonresidential real property used as an integral part of a "qualified production activity" — manufacturing, production, or refining of tangible personal property — taxpayers can elect 100% expensing of the structure itself, not just its equipment.
The eligibility window is tight: construction must begin after January 19, 2025 and before January 1, 2029, with the property placed in service before January 1, 2031. Office areas, R&D space, parking, sales space, and finished-goods storage are excluded. There is a 95% de minimis rule that lets you treat an entire building as QPP if at least 95% of the interior is used for production. And there is a 10-year recapture rule: convert the building to a non-production use within ten years and you give the benefit back.
For most small businesses Section 168(n) will not apply. For owners considering a new fabrication shop, food-processing facility, or production-line build-out, however, it is worth speaking with a tax advisor before breaking ground.
A Few Strategic Considerations
A full first-year deduction is alluring, but it is not always optimal. Before automatically taking 100% bonus depreciation, think through:
- Marginal-rate timing. If you expect higher income (and a higher marginal rate) in 2027 than in 2026, spreading depreciation may save more total tax. The election to use the 40% TCJA rate for the first tax year ending after January 19, 2025 exists for exactly this reason.
- State income tax exposure. Several large states — California, New York, and others — decouple from federal bonus depreciation. Taking the full federal write-off creates a state-federal book-tax difference you will have to track for years.
- Qualified Business Income (QBI) deduction interaction. The Section 199A deduction is capped at 20% of QBI. Aggressive depreciation that shrinks QBI to zero or below also shrinks your potential QBI deduction.
- Loan-covenant impact. Lenders often track adjusted EBITDA. Depreciation is added back, so this is usually neutral, but check your specific covenant definitions before accelerating large write-offs.
- Asset disposition mechanics. When you sell or scrap fully depreciated property, the full proceeds are recaptured as ordinary income up to the depreciation taken. Plan for that bill before you celebrate the deduction.
Bookkeeping Habits That Make the Deduction Defensible
The deduction itself is a single line on Form 4562, but the calculations behind it depend on records that have to be kept long before tax season. Three practices will save you the most pain:
- Track acquisition dates separately from placed-in-service dates. These are different concepts and the IRS asks for both. Most off-the-shelf bookkeeping tools record only one. Maintaining a side schedule — by asset — protects you on examination.
- Itemize contractor invoices for QIP work. When you sign a build-out agreement, ask the contractor to provide a cost breakdown by category: interior finishes, HVAC, plumbing, electrical, structural, exterior, and so on. The breakdown is what lets you separate eligible from ineligible spend.
- Maintain a fixed-asset register that survives accounting-software changes. Many businesses lose depreciation history when they migrate platforms. A plain-text or spreadsheet register that you control — not just what your software reports — is the only durable record of basis, accumulated depreciation, and remaining life. This matters most when you sell or dispose of the asset years later.
Keep Your Capital Asset Records Audit-Ready
Permanent 100% bonus depreciation is a real opportunity, but the audit risk has not gone away. The IRS already publishes its disagreements with aggressive QIP and QPP positions, and the new acquisition-date rules give examiners a fresh angle. Clean records — covering acquisition dates, written binding contracts, placed-in-service dates, itemized improvement costs, and per-asset basis schedules — are the difference between a confident claim and a costly adjustment.
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