An INEOS Grenadier can be written off as a business tax deduction, and in most cases the entire purchase price can come off your federal taxable income in the first year. The vehicle’s gross vehicle weight rating of roughly 7,716 pounds clears the 6,000-pound threshold that separates ordinary passenger cars from heavy vehicles eligible for accelerated deductions, and the One Big Beautiful Bill Act restored 100% bonus depreciation for qualifying property placed in service after January 19, 2025. Combine that with Section 179 expensing and a business owner buying a 2026 Grenadier can deduct the full cost in year one, provided business use exceeds 50%.
Why the Weight Rating Matters
Federal tax law draws a hard line at 6,000 pounds GVWR. Below it, depreciation on a vehicle is capped tightly under the luxury auto rules. Above it, the caps loosen and much larger first-year deductions open up. GVWR is not curb weight — it is the manufacturer’s maximum rated operating weight, printed on the door jamb sticker.
Every U.S. Grenadier trim clears the threshold. The base Grenadier, Trialmaster, Fieldmaster, and Quartermaster all carry a GVWR of approximately 7,716 pounds, comfortably above 6,000 and below the 14,000-pound ceiling where commercial truck rules would take over. The 2026 model year starts at $72,995.
The 50% Business Use Rule
None of the accelerated deductions apply unless you use the Grenadier more than 50% of the time for business. That is a bright-line test in 26 U.S.C. § 280F: if business use falls to 50% or less in any year, you lose access to both Section 179 expensing and bonus depreciation for that vehicle.1Office of the Law Revision Counsel. 26 USC 280F – Limitation on Depreciation for Luxury Automobiles
The deduction also scales to the business-use percentage. Drive the Grenadier 80% for work and 20% for personal errands, and only 80% of the vehicle’s cost is deductible. Business use includes driving to client sites, between offices, to job locations, and for deliveries. It does not include the daily commute from home to your regular office; the IRS treats that as personal mileage regardless of what you do when you arrive.
A contemporaneous mileage log — date, destination, business purpose, miles — is what the IRS looks for. Reconstructing one after the fact rarely holds up.
Section 179 Deduction for 2026
Section 179 lets you deduct the cost of a qualifying business asset in the year you buy it rather than spreading it over multiple years. For heavy SUVs like the Grenadier, that deduction is capped. The most recently published IRS figure for SUVs in this weight class is $31,300.2Internal Revenue Service. Rev. Proc. 2024-40 The cap exists because the Grenadier fits the code’s definition of a sport utility vehicle: a four-wheeled passenger vehicle rated between 6,000 and 14,000 pounds GVWR.3Office of the Law Revision Counsel. 26 USC 179 – Election to Expense Certain Depreciable Business Assets
The Quartermaster, the pickup variant, may escape the SUV cap. The statute excludes vehicles with an open or cap-enclosed cargo area at least six feet long that is not directly accessible from the passenger compartment. If the Quartermaster’s bed meets that measurement, it qualifies for the full Section 179 limit of $2,560,000 for 2026 rather than the $31,300 SUV cap. Measure the bed, or confirm the spec with the dealer, before assuming the higher deduction applies.
A few other rules cut across all trims. The vehicle must be purchased and placed in service during the tax year, meaning available and ready for business use, not just ordered. Financing does not disqualify you; the deduction is based on the full cost, not the down payment. And the overall Section 179 deduction begins phasing out dollar-for-dollar once total equipment purchases for the year exceed $4,090,000.3Office of the Law Revision Counsel. 26 USC 179 – Election to Expense Certain Depreciable Business Assets
100% Bonus Depreciation Is Back
This is where the math changed. The One Big Beautiful Bill Act, signed on July 4, 2025, permanently restored 100% first-year bonus depreciation for qualified property acquired after January 19, 2025.4Internal Revenue Service. Treasury, IRS Issue Guidance on the Additional First Year Depreciation Deduction Amended as Part of the One Big Beautiful Bill The prior phase-down is gone.
Bonus depreciation applies to whatever cost remains after your Section 179 deduction. It has no annual dollar cap and is not limited to your taxable business income for the year. If the deduction exceeds your income, it can create a net operating loss that carries forward to offset future taxes.5Office of the Law Revision Counsel. 26 USC 168 – Accelerated Cost Recovery System
For a Grenadier buyer in 2026, that combination means the entire purchase price can be deducted in year one: the Section 179 portion up to the SUV cap, and 100% bonus depreciation on everything left over.
What the Numbers Look Like
Assume a business owner buys a 2026 Grenadier Fieldmaster for $80,000 and uses it 100% for business:
- Section 179 deduction: $31,300 (the SUV cap)
- Remaining cost basis: $48,700
- 100% bonus depreciation: $48,700
- Total first-year deduction: $80,000
At a 37% marginal federal tax rate, that $80,000 deduction saves roughly $29,600 in federal income tax. At 24%, the savings come to about $19,200.
Now adjust for mixed use. At 75% business use, the deductible cost basis drops to $60,000. Section 179 still delivers its full $31,300 because 75% of $80,000 exceeds that cap. Bonus depreciation then covers the remaining $28,700 in eligible basis. Total first-year deduction: $60,000, with tax savings scaling accordingly.
Leasing Works Differently
Section 179 and bonus depreciation only apply when you own the vehicle. A standard operating lease, where the leasing company holds the title, does not qualify. Under a lease, you instead deduct the business-use percentage of the monthly payments, insurance, fuel, and maintenance as ordinary business expenses. Smaller per year, spread across the lease term.
A capital or finance lease that includes a buyout obligation or effectively transfers ownership can be treated as a purchase, opening the door to Section 179 and bonus depreciation. The distinction depends on the contract terms, not the label the dealer uses. Have the agreement reviewed before assuming accelerated deductions apply.
For high-value vehicles under a standard lease, the IRS also requires an “inclusion amount,” a small add-back to income when the vehicle’s fair market value exceeds an annually published threshold. It is a minor adjustment, but another reason the purchase route tends to deliver larger upfront tax benefits on an expensive vehicle.
Depreciation Recapture When You Sell
The IRS gives you the deduction up front, but there is a catch on the back end. When you sell, trade in, or otherwise dispose of the Grenadier, any gain up to the total amount of depreciation you previously claimed is taxed as ordinary income, not at the lower capital gains rate.6Internal Revenue Service. Publication 544 – Sales and Other Dispositions of Assets
Say you deducted the entire $80,000 in year one, bringing your basis to zero, and sold the Grenadier three years later for $35,000. That full $35,000 is ordinary income because it falls within the depreciation you claimed. You report the recapture on Form 4797.7Internal Revenue Service. Instructions for Form 4797
Recapture does not erase the benefit. You got the full deduction at your marginal rate in year one and pay recapture only when you sell, sometimes years later. The time value of that deferral is real. But treating the deduction as free money and then being surprised at trade-in is the most common mistake in vehicle write-offs.
If Business Use Drops Below 50%
Selling is not the only trigger. If business use falls to 50% or less in any year after you claimed the accelerated deductions, you must recapture the excess depreciation, meaning the difference between what you deducted under Section 179 and bonus depreciation and what you would have deducted using slower straight-line depreciation over the recovery period.8Internal Revenue Service. Instructions for Form 4562 That difference becomes ordinary income in the year use drops, again on Form 4797. Going forward, you switch to straight-line depreciation on the remaining basis.
The practical implication: plan to keep business use above 50% for the full five-year MACRS recovery period. Some owners protect the deduction by keeping a separate personal vehicle and reserving the Grenadier for work.
State Taxes Don’t Always Follow
Federal deductions do not automatically carry to your state return. A number of states have decoupled from federal 100% bonus depreciation, meaning your state taxable income can be higher than your federal taxable income for the same vehicle. California, Illinois, Michigan, Delaware, and Maine are among the states that have explicitly limited or blocked bonus depreciation as of late 2025, along with the District of Columbia.9National Conference of State Legislatures. 2025 Tax Conformity Changes
Some states also set their own Section 179 limits below the federal amount. Check state conformity before pricing out an after-tax cost, or you may find the state bill higher than expected.
How to File the Deduction
Both Section 179 and bonus depreciation go on IRS Form 4562, Depreciation and Amortization. Part I handles the Section 179 election; Part II covers the special depreciation allowance.8Internal Revenue Service. Instructions for Form 4562 You enter the vehicle’s total cost, the date placed in service, and your business-use percentage.
Form 4562 attaches to your income tax return. Sole proprietors and single-member LLCs file it with Form 1040, typically via Schedule C. Corporations file it with Form 1120.10Internal Revenue Service. About Form 1120, U.S. Corporation Income Tax Return Get the “placed in service” date right — it is the day the vehicle was actually available for business use, which may differ from the purchase date if delivery was delayed.
Keep the Records
The IRS requires you to keep records supporting any deduction for at least three years after filing the return that claims it.11Internal Revenue Service. How Long Should I Keep Records For a deduction of this size, that means the purchase agreement, financing documents, and a mileage log for every year you own the Grenadier.
Large vehicle deductions draw attention. An $80,000 first-year write-off on a Schedule C is the kind of line item that can prompt a closer look, and without a mileage log showing business use above 50% the IRS can disallow the entire accelerated deduction. Add a 20% accuracy-related penalty on the resulting underpayment, plus interest.12Internal Revenue Service. Accuracy-Related Penalty A smartphone app that logs trips automatically costs almost nothing and protects a five-figure deduction.