You should capitalize a leasehold improvement whenever you, as the tenant, pay for work that permanently attaches to the leased space and meets the IRS definition of a betterment, restoration, or adaptation rather than a repair. Once capitalized, the cost is recovered over 15 years for federal tax purposes as qualified improvement property (with 100% bonus depreciation or Section 179 available to accelerate it), and amortized over the shorter of the improvement’s useful life or the remaining lease term for GAAP financial reporting. Small expenditures that fall under the de minimis safe harbor can still be expensed in the year they’re incurred.
Repair or Improvement: The Threshold Test
The first question is whether the expenditure is an improvement at all. The IRS tangible property regulations require capitalization if a cost results in any one of three outcomes.1Internal Revenue Service. Tangible Property Final Regulations
- A betterment: the cost fixes a pre-existing defect, adds to the property’s physical size or capacity, or materially increases its productivity, efficiency, or output.
- A restoration: the cost replaces a major component or substantial structural part, returns a non-functional property to working condition, or rebuilds it to like-new condition after its class life ends.
- An adaptation: the cost converts the property to a use that is fundamentally different from its original purpose when first placed in service.
Building new interior walls, installing a dedicated HVAC system, or adding built-in cabinetry satisfies at least one of these tests. Repainting an office, patching drywall, or replacing worn carpet generally does not, because those activities maintain the property in its current condition without materially adding value or capacity. Capitalizing a true repair inflates your balance sheet; expensing a true improvement accelerates deductions you aren’t entitled to.
The De Minimis Safe Harbor
Even work that technically qualifies as an improvement can be deducted immediately if it falls under the de minimis safe harbor. A business with an applicable financial statement (an audited set of financials, an SEC filing, or certain other specified statements) can expense items costing up to $5,000 per invoice or per item. A business without one can expense items up to $2,500 per invoice or per item.1Internal Revenue Service. Tangible Property Final Regulations
You elect this safe harbor annually by attaching a statement to your tax return. The election applies to all qualifying expenditures for the year, so you can’t cherry-pick which items run through it. For a tenant making dozens of small modifications during a build-out, the election can eliminate a significant amount of tracking and depreciation scheduling.
What Qualifies as a Leasehold Improvement
A leasehold improvement is any modification to a leased space that permanently attaches to the building and reverts to the landlord when the lease ends. In practical terms, it’s anything you can’t take with you when you move out. These items become fixtures and are capitalized on the tenant’s books.
Movable items the tenant owns independently (freestanding furniture, computer equipment, modular shelving) are not leasehold improvements. Those assets are capitalized separately under their own MACRS class lives, typically five or seven years depending on the asset.2Internal Revenue Service. Publication 946 – How to Depreciate Property
When you compute the capitalized cost, include everything directly tied to the physical work: architectural and engineering fees, permits, construction labor, and materials. These soft costs are part of the improvement’s basis and get recovered alongside the hard construction costs.
How Fast You Recover the Cost for Tax
Most leasehold improvements to commercial space qualify as qualified improvement property (QIP), defined as any improvement a taxpayer makes to the interior of a nonresidential building, placed in service after the building itself was first placed in service.3Legal Information Institute. 26 U.S. Code 168(e)(6) – Qualified Improvement Property Definition Four categories are excluded:
- Enlargement of the building’s footprint or volume
- Elevators and escalators
- The building’s internal structural framework (load-bearing walls, columns, girders, beams, trusses)
- Improvements to residential rental property
QIP has a 15-year MACRS recovery period, far shorter than the 39-year period that applies to nonresidential real property generally.4Office of the Law Revision Counsel. 26 U.S. Code 168 – Accelerated Cost Recovery System Any improvement that falls outside the QIP definition still gets capitalized but recovers over 39 years using straight-line depreciation.
100% Bonus Depreciation
The One Big Beautiful Bill Act permanently restored 100% first-year bonus depreciation for qualifying property acquired after January 19, 2025. Because QIP has a 15-year recovery period, well under the 20-year ceiling for bonus-eligible property, a tenant who places qualifying improvements in service can deduct the entire cost in year one.5Internal Revenue Service. Treasury, IRS Issue Guidance on the Additional First Year Depreciation Deduction The 100% rate is now permanent with no scheduled expiration.6Internal Revenue Service. One, Big, Beautiful Bill Provisions
Section 179 Expensing
As an alternative to bonus depreciation, you can elect to expense QIP costs under Section 179. The base deduction ceiling is $2,500,000, with a phase-out that begins when total qualifying property placed in service during the year exceeds $4,000,000.7Office of the Law Revision Counsel. 26 U.S. Code 179 – Election to Expense Certain Depreciable Business Assets These amounts are adjusted annually for inflation beginning with tax years after 2025; for 2026 the inflation-adjusted deduction limit is approximately $2,560,000 with a phase-out near $4,090,000.
Section 179 also caps the deduction at the taxpayer’s taxable income from active trades or businesses for the year, with any excess carrying forward. That income limitation is what makes Section 179 less flexible than bonus depreciation for businesses with thin margins or operating losses. Bonus depreciation, by contrast, can generate or increase a net operating loss.
How Fast You Amortize for GAAP
Tax rules and financial reporting rules diverge sharply here. Under GAAP (ASC 842), leasehold improvements are amortized over the shorter of the improvement’s useful life or the remaining lease term. If the lease transfers ownership to you, or you are reasonably certain to exercise a purchase option, you can amortize over the full useful life regardless of the lease term.
The “remaining lease term” is not simply the years left on your current contract. ASC 842 defines it as the noncancelable period plus any renewal option periods the tenant is reasonably certain to exercise.8Deloitte Accounting Research Tool. Deloitte’s Roadmap: Leases – 5.2 Lease Term Reasonable certainty is a high bar: it requires a strong economic incentive to renew, not just the contractual right. Significant leasehold improvements, below-market renewal rates, and a location critical to the business all push toward reasonable certainty.
The distinction has real consequences. Install $400,000 in improvements with a 20-year useful life on a 10-year lease with a renewal option, and the renewal question is the difference between $40,000 and $20,000 in annual amortization. Making a substantial investment in improvements can itself be evidence of reasonable certainty to renew, because walking away from that investment would be economically irrational.
Why the Tax Number and the GAAP Number Won’t Match
The tax recovery period and the GAAP amortization period are calculated under completely different rules and will almost never match.
For tax, QIP is always recovered over 15 years straight-line unless you elect bonus depreciation or Section 179 to accelerate it. The lease term is irrelevant. A $200,000 improvement on a 7-year lease still has a 15-year tax recovery period.4Office of the Law Revision Counsel. 26 U.S. Code 168 – Accelerated Cost Recovery System Non-QIP improvements recover over 39 years.
For GAAP, that same $200,000 improvement on a 7-year lease with no reasonably certain renewal is amortized over 7 years. The depreciation on Form 4562 will differ from the amortization expense on your income statement, creating a book-tax difference that has to be tracked.9Internal Revenue Service. About Form 4562, Depreciation and Amortization
When the Lease Ends Early or Gets Extended
Early Termination
If you vacate before the lease expires, the unamortized balance of your improvements must be written off immediately. For financial reporting, you recognize the remaining book value as a loss in the period the lease ends. If $70,000 of unamortized improvements remain when you surrender the space, that full amount hits the income statement as a disposal expense.
Tax treatment follows a similar path. Treasury regulations governing MACRS dispositions apply to a lessee with a depreciable basis in an improvement who disposes of it before or at lease termination.10eCFR. 26 CFR 1.168(i)-8 – Dispositions of MACRS Property You deduct the remaining tax basis as an ordinary loss in the year of disposition, reported on Form 4562.
Renewal or Extension
When you renew or extend, you don’t restart the clock on improvements already on the books. Instead, the remaining unamortized cost is spread over the new remaining period, using the shorter of the improvement’s remaining useful life or the extended lease term. The adjustment is prospective; prior periods aren’t restated. The unamortized balance is simply divided by the new, longer remaining timeline, reducing annual expense going forward.
Tenant Improvement Allowances
Landlords frequently offer cash allowances to offset a tenant’s build-out costs, and the treatment depends on what the allowance covers and how the lease reads. Under IRC Section 110, a tenant can exclude a construction allowance from gross income if three conditions are met: the lease is for retail space, the lease term is 15 years or less, and the allowance funds the construction of permanent real property improvements that revert to the landlord when the lease ends.11Office of the Law Revision Counsel. 26 U.S. Code 110 – Qualified Lessee Construction Allowances for Short-Term Leases
When Section 110 applies, the landlord is treated as the tax owner of the improvements. The tenant excludes the allowance from income and has no depreciable basis in the improvements the allowance funded. The exclusion is limited to the amount actually spent on qualifying improvements, so any excess allowance is taxable income.
The lease itself must explicitly state that the allowance is for constructing or improving qualified long-term real property at the leased space. Vague language won’t satisfy this. If the allowance doesn’t meet the Section 110 safe harbor (for example, the space is office rather than retail, or the lease exceeds 15 years), the allowance is generally treated as taxable rent to the tenant, who then capitalizes and depreciates the improvements under the normal QIP rules.
Penalties for Getting It Wrong
Misclassifying a capital improvement as a deductible repair, or the reverse, creates a tax underpayment or overpayment the IRS can flag on audit. The accuracy-related penalty under IRC Section 6662 applies a 20% penalty on the underpayment amount when the error results from negligence or a substantial understatement of income. For gross valuation misstatements, the penalty doubles to 40%.
The penalty doesn’t apply if you can demonstrate reasonable cause and good faith. Contemporaneous documentation of why each expenditure was classified as a repair or improvement is the best defense: keep the invoices, the contractor’s scope of work, and a written analysis applying the betterment, restoration, and adaptation tests at the time the money is spent, not years later when an auditor asks.