What is a buy vs lease commercial property analysis? A buy vs lease commercial property analysis is an after-tax comparison of the total cost of owning the building your business occupies against the cost of renting comparable space over the same time horizon, reduced to a single net present value so the two paths can be judged on identical terms. A buy vs lease commercial property AI analysis uses tools like ChatGPT, Claude, and Gemini to build that model in an afternoon, stress test the assumptions that actually move the answer, and expose where a broker pro forma quietly favors one outcome. For the broader financing context, see our guide to AI CRE finance capital markets.
Key Takeaways
- Buying and leasing are not compared by monthly payment. They are compared by after-tax net present value of total occupancy cost over a defined hold period.
- The answer usually turns on four inputs: your discount rate, the residual value at exit, the rent growth you avoid by owning, and your effective tax rate.
- Permanent 100 percent bonus depreciation, restored for property acquired after January 19, 2025, materially improved the after-tax case for buying.
- SBA 504 financing lets an operating business buy its building with roughly 10 percent down if it occupies at least 51 percent of an existing property.
- Owning converts a fully deductible operating expense into an illiquid, concentrated asset. AI models the tradeoff but cannot price your need for flexibility.
Buy vs Lease Commercial Property AI Analysis Explained
A buy vs lease commercial property AI analysis compares two cash flow streams over the same period, typically 10 years. The lease stream is base rent plus operating expense pass-throughs, escalated annually, net of the tax deduction. The ownership stream is the down payment, debt service, taxes, insurance, maintenance, and capital reserves, offset by depreciation deductions and the after-tax proceeds at sale.
The mistake almost every business owner makes is comparing a lease payment to a mortgage payment. Mortgage principal is equity accumulation rather than expense, the owner carries roof, HVAC, and parking lot costs a gross-lease tenant never sees, and the tenant keeps capital in the business that the owner has locked into a down payment.
The Inputs That Actually Decide the Answer
Four assumptions drive nearly all of the variance in a buy vs lease model, and everything else is rounding. Get them wrong and a sophisticated model produces a confident wrong answer.
- Discount rate: Use the return your business earns on capital deployed internally, not a savings rate. A company compounding at 20 percent on inventory has a very high hurdle for tying up cash in a building.
- Residual value: What the property is worth at the end of the hold. This input often swings the result more than the entire operating comparison, so it deserves a range rather than a point estimate.
- Rent growth avoided: Owning fixes your largest occupancy cost. If comparable rents escalate at 3 percent annually, a 10 year lease costs meaningfully more in year 10 than year 1, while a fixed-rate mortgage payment does not move.
- Effective tax rate: Rent is fully deductible; ownership generates interest and depreciation deductions instead. The higher your marginal rate, the more that shield is worth.
Ask your AI tool for a sensitivity table across residual value and discount rate simultaneously. You are not looking for a single answer but for the crossover point, the exit value at which buying stops winning. If buying only wins when the building appreciates 4 percent annually for a decade, you are not making a real estate decision, you are making a bet on appreciation.
What Changed in 2026: Depreciation and Cheap Owner-Occupied Debt
Two 2026 realities have shifted the math toward ownership relative to the analysis a business owner would have run in 2023. Both are worth modeling explicitly rather than assuming. First, depreciation. The One Big Beautiful Bill Act permanently restored a 100 percent special depreciation allowance for qualifying property acquired and placed in service after January 19, 2025, eliminating the phase-down that would have cut bonus depreciation to 20 percent in 2026. Per IRS Publication 946, this applies to property with a recovery period of 20 years or less. The building shell, depreciated over 39 years for nonresidential property, does not qualify. That is why a cost segregation study matters: it reclassifies 5 year personal property, 7 year fixtures, and 15 year land improvements out of the shell so those components can be expensed immediately, producing a first-year deduction a lease cannot generate.
Second, financing. An operating business buying its own building is not a normal commercial borrower. The SBA 504 program, which pairs a conventional bank first mortgage with a fixed-rate debenture from a Certified Development Company, lets an eligible business buy with roughly 10 percent down against the 20 to 30 percent a conventional commercial mortgage requires. It is restricted to owner-occupied real estate and excludes speculative or investment property. The SBA-backed portion is generally capped at $5.5 million, though total project size can run higher because the bank's first mortgage is not subject to that cap. Our guide to AI for SBA 504 and 7(a) loans covers eligibility and structuring in detail.
The occupancy test is the gate, and it is also an opportunity. Your business generally must occupy at least 51 percent of an existing building, meaning you can buy a larger property, occupy just over half, and lease the balance. That third-party rent is a real model input and frequently what tips a marginal deal.
Building the Comparison With AI: A Working Prompt Sequence
Run this as three prompts rather than one. A single mega-prompt produces a confident narrative; a sequence produces a model you can audit. Upload the lease proposal and term sheet as files rather than pasting summaries, because the escalation clauses and pass-through language matter.
- Extract: "From the attached lease proposal, extract base rent by year, escalation rate, operating expense structure, renewal options, and any tenant improvement allowance. From the term sheet, extract price, loan amount, rate, amortization, and term. Return a table and flag anything ambiguous rather than assuming."
- Model: "Build a 10 year after-tax cash flow for both paths at a 28 percent effective tax rate and a 12 percent discount rate. For ownership, assume a 39 year shell, cost segregation reclassifying 22 percent of basis to 5, 7, and 15 year property with 100 percent bonus in year one, and a year 10 sale at a 6.5 percent cap rate applied to imputed net operating income. Show the NPV of each path and your formulas."
- Break it: "Re-run across exit cap rates from 5.5 to 8.0 percent and discount rates from 8 to 20 percent. Identify where leasing becomes the better decision, then argue the strongest case against buying."
The third prompt is the one that matters. AI defaults to agreeable, and a model that only tells you buying wins is not analysis. Asking it to argue the other side surfaces the assumptions doing the heavy lifting. Since the lease side depends on terms you can still negotiate, read our AI lease renewal negotiation playbook before treating a landlord's first proposal as fixed.
Reading the Output: When Buying Actually Wins
Buying wins under a narrower set of conditions than most brokers suggest, and an honest model shows which of them you actually meet: a stable business unlikely to outgrow or shrink out of the space during the hold, a building generic enough to re-let or sell, a marginal tax rate high enough to make the depreciation shield valuable, and capital that is not scarce inside the operating business.
Leasing wins when the business is growing fast, when the space is specialized, when the down payment would otherwise fund inventory or hiring at a high return, or when the owner expects to sell the company within the hold period. A buyer of your business may not want your building.
One caution the model will not raise on its own: the down payment is rarely the only capital at risk. In the Federal Reserve's Small Business Credit Survey, 59 percent of small firms carrying debt used a personal guarantee to secure it. If your operating line is already personally guaranteed, adding a guaranteed mortgage concentrates far more personal exposure than the spreadsheet shows. Since rate assumptions move the ownership case substantially, pair this with our approach to AI interest rate sensitivity analysis before locking a structure. For owners who want a second set of eyes on a live decision, The AI Consulting Network pressure tests these models before anything gets signed.
Frequently Asked Questions
Q: Is it cheaper to buy or lease commercial property?
A: Neither is reliably cheaper. On an after-tax net present value basis over a 10 year hold, buying typically wins when the property holds its value and the owner has a high marginal tax rate. Leasing wins when the business can redeploy the down payment at a higher return.
Q: How much down payment do I need to buy my business's building?
A: A conventional commercial mortgage generally requires 20 to 30 percent down. An SBA 504 loan can cut that to roughly 10 percent for an eligible business occupying at least 51 percent of an existing building, though newer businesses are often asked for 15 to 20 percent.
Q: Can AI actually run a buy vs lease analysis correctly?
A: AI builds the model structure and runs sensitivities well, but it accepts whatever residual value and discount rate you supply without challenge. Ask it to show its formulas and argue the opposite conclusion, and have a CPA confirm the depreciation assumptions before you rely on the output.
Q: What is the most common error in these analyses?
A: Comparing a monthly lease payment to a monthly mortgage payment. That treats loan principal as expense when it is equity accumulation, and ignores the roof, HVAC, and capital reserve costs an owner absorbs that a gross-lease tenant does not.
If you are weighing an owner-occupied purchase against a renewal proposal, reach out to Avi Hacker, J.D. at The AI Consulting Network.