The choice between an NNN vs gross lease in commercial real estate is not a formatting question the broker resolves before the offering memorandum prints. It is a decision about who carries operating-cost risk — and that decision moves real dollars between landlord and tenant every year of the term. Treat it as a given and you inherit an expense-recovery structure you never stress-tested. Treat it as a negotiated variable and it becomes a lever on both your cap-rate math and your downside.
Three structures dominate the market, and they differ on one axis: how operating expenses flow. Get that axis right and the rest of the underwriting follows. Get it wrong and your net yield is an estimate dressed up as a number.
The three structures, by who carries the cost
Strip away the jargon and each structure is a different answer to a single question — when property taxes, insurance, and maintenance rise, whose problem is it?
| Lease structure | Who pays taxes, insurance, CAM | Who carries cost risk |
|---|---|---|
| Triple-net (NNN) | Tenant | Tenant — landlord still bears vacancy and rollover |
| Modified gross | Split or negotiated by category | Shared — read the clause |
| Full-service gross | Landlord | Landlord — operating-cost inflation is yours |
- Triple net (NNN) — the tenant pays base rent plus its pro-rata share of taxes, insurance, and common-area maintenance. The landlord's cash flow is clean: rent in, rent out, minimal expense leakage. Operating-cost unpredictability sits with the tenant.
- Gross (full-service) — the tenant pays one fixed rent and the landlord absorbs every operating expense. The landlord carries the full risk that taxes reassess, insurance premiums spike, or a roof fails. The tenant's cost is fixed; the landlord's net is not.
- Modified gross — the negotiated middle. The tenant covers some costs, the landlord covers others, and the carve-outs are deal-specific. A base-year stop, a tenant-paid utility line, a landlord-retained structural obligation — modified gross is whatever the two parties wrote down, which is exactly why it cannot be trusted on a label.
The error operators make is reading the lease type off the rent roll and moving straight to the cap-rate calculation. The structure tells you who is exposed; only the document tells you to what degree.
NNN lease risk the landlord still carries
NNN is sold as the landlord's clean structure, and for cash-flow modeling it is. But "net" is a spectrum, not a guarantee. The risk does not disappear — it relocates, and on a weak lease it relocates back to you.
- Expense caps and exclusions — many NNN leases cap controllable CAM increases or exclude capital items entirely. If the roof and parking lot are landlord obligations, you are holding a hybrid, not a true triple net.
- Credit behind the obligation — a triple-net lease only shifts cost risk as far as the tenant is good for it. A 15-year NNN term backed by a thin operator is a gross lease waiting for a default. The reimbursement clause is only as strong as the entity signing it.
- Rollover at expiration — the cleaner the in-place NNN, the harder the re-tenanting hit when it expires, because the next tenant negotiates from scratch. Term length and structure interact; you cannot read one without the other.
This is why a label is never enough. The questions that decide whether an NNN actually protects you live in the reimbursement language, the exclusions, and the tenant's balance sheet — the same fields a disciplined lease abstract built as a decision tool is designed to surface before any pricing assumption hardens. Our walkthrough of what a commercial lease abstract should include lays out the exact field set.
Why gross and modified gross demand a stress test
A gross lease pulls operating-cost risk back onto the landlord, which means the underwriter is now pricing a forecast. Every dollar of taxes, insurance, and maintenance you assume is an assumption that can be wrong — and on a long gross lease, a 4% annual expense drift compounds into a materially lower net than the day-one number suggests.
Modified gross is worse, not because it is riskier, but because it hides. A base-year expense stop means the landlord eats every increase above year one — a benign-looking clause that turns into the single largest variable in a reassessment market. The work is line-by-line:
- Identify the carve-outs — read which expenses pass through, which are capped, and which the landlord retains in full. Never trust the summary line in the OM.
- Stress the expense assumptions — model taxes at a post-sale reassessed basis, not the seller's in-place number, and pressure-test insurance and CAM against actual market trend, not a flat growth rate.
- Reconcile to the cap rate — only after the expense recovery is mapped does the going-in cap rate mean anything. The same building can price 50 basis points apart depending on whether the lease is true NNN or modified gross with a soft stop.
This is the heart of disciplined net-lease and gross-lease underwriting — and the reason the lease structure has to be resolved before the math, not after. Our sequence for how to underwrite a net-lease acquisition walks the expense-recovery analysis in full.
The decision: when each structure wins
There is no universally correct structure — there is a correct structure for a given tenant, term, and objective. The recommendation flips on three variables.
- Tenant credit quality — strong credit favors NNN. An investment-grade or well-capitalized tenant makes the cost-shift real and durable, and the clean cash flow compresses your underwriting risk. Weak credit erodes the benefit; the cleaner the lease reads, the more it depends on a tenant who may not perform.
- Remaining lease term — long term favors NNN, because you want the expense risk shifted across the years you are exposed. Short remaining term pulls the decision toward gross or modified gross, where you control the property and can reposition rather than inherit a soon-to-expire pass-through.
- What you are optimizing for — if you are buying underwriting simplicity and clean, financeable cash flow, NNN is the answer. If you are optimizing for net-yield compression and you have the operating capacity to manage expenses actively, a gross or modified-gross structure can deliver more net per dollar — at the cost of a harder forecast.
The default recommendation: for most passive owners and lenders, a true NNN lease behind real credit on a long term is the right structure — it cleans up the model and shifts the risk you do not want to manage. The condition that flips it: when the tenant credit is thin, the term is short, or you are an operator buying for yield rather than simplicity, the gross and modified-gross structures stop being inferior and start being the right tool — provided you have actually stress-tested the expenses instead of trusting the label. The structure choice and the audience for the analysis are linked; the way you frame it for an investment committee versus a lender is exactly the distinction we draw in IC memo vs. decision memo vs. lender memo.
One schema, every lease
The reason structure gets treated as a given is that comparing leases is tedious — a 47-lease portfolio with a mix of NNN, gross, and modified-gross terms reads as 47 different documents until someone forces them onto one schema. That is the work: abstract every lease to the same expense-recovery fields, reconcile each one to a reassessed expense base, and only then trust the cap-rate comparison across the set. Do it once per deal and the structure decision stops being a label you inherited and becomes a number you can defend — which is the whole point of treating the lease as a decision rather than a description.
Pick the structure by who should carry operating-cost volatility, then price it — never let the lease type default because the broker dropped it in.
Need this on a live deal? Capistrano produces underwriting, lease abstracts, investment memos, and capital-raise materials — AI-leveraged, principal-reviewed.