NNN Property Acquisition Due Diligence: Lease Review Checklist
When You Buy an NNN Property, You're Buying the Lease
The property itself — the land, the building, the parking lot — is almost secondary. What you're actually acquiring is the income stream the lease creates and the risk exposure hidden inside the lease language.
A well-underwritten NNN acquisition starts with a complete lease review, done before the tenant knows a sale is in process. Once a seller discloses the transaction to a major tenant, leverage shifts. Tenants in this situation may start asking questions about SNDA agreements, lender consent requirements, or renewal option windows. The time to understand what you're buying is before any of that happens.
This checklist covers the key items that deserve close scrutiny in every NNN lease review before acquisition close.
---
1. Rent Schedule and Escalation Clauses
Start with the rent. You need to know not just what the tenant pays today, but what they will pay every year through lease expiration.
What to pull from the lease:
- Current base rent
- Scheduled rent bumps — fixed percentage increases (e.g., 10% every five years), CPI-linked adjustments, or flat dollar increases
- Bump dates and the calculation method for CPI adjustments if applicable
- Any rent abatement periods remaining — check carefully if the tenant received a free-rent period at lease inception that hasn't fully burned off
Where landlords get surprised: CPI-linked escalation clauses that look modest in a low-inflation environment can produce unexpected outcomes when inflation spikes. Understand what the formula actually computes, not just what the rate has historically been.
---
2. CAM Cap and Exclusions
Common Area Maintenance costs are where NNN economics can shift materially. A lease with a favorable CAM cap can protect the tenant's effective rent burden — at the landlord's expense.
What to pull from the lease:
- Whether CAM charges are capped, and if so, what percentage
- Whether the cap applies to all operating expenses or only controllable expenses (most well-drafted caps apply only to controllable costs, excluding things like property taxes and insurance)
- Which expense categories are explicitly excluded from CAM recovery — management fees, capital expenditures, ground lease payments, and costs that benefit other tenants are common exclusions
- Whether gross-up provisions apply if the property isn't fully occupied
Where landlords get surprised: CAM exclusion language compounds over time. A tenant who excluded roof replacement from CAM at signing may effectively force the landlord to absorb the full cost of a $300,000 roof replacement out of pocket.
For a detailed breakdown of how gross-up provisions work, see our guide to NNN gross-up calculations.
---
3. Co-Tenancy Triggers
If the property has more than one tenant — or if the target tenant's lease contains a co-tenancy clause — this section deserves particular attention.
What to pull from the lease:
- Whether the tenant has any co-tenancy rights at all
- What triggers the co-tenancy clause: a named anchor tenant vacancy, occupancy falling below a defined percentage, or both
- What the remedy is: rent reduction, termination right, or some combination
- Whether there's a cure period — often the landlord has 90–180 days to cure a co-tenancy failure before the tenant's remedy activates
Where landlords get surprised: Co-tenancy clauses can be silent on what constitutes "vacancy" — a dark tenant who is still paying rent may or may not trigger the clause depending on lease language. This is particularly relevant when reviewing properties with major retail anchor exposure.
---
4. Dark Clause Provisions
A dark clause governs what happens when a tenant stops operating at the location but continues paying rent. This is more common than it sounds — large chains will sometimes keep leases alive on underperforming locations to protect co-tenancy agreements at nearby stores.
What to pull from the lease:
- Whether the tenant has any continuous operation obligation
- If not, whether the landlord has any recapture right when a tenant goes dark
- How long a tenant can remain dark before the landlord can reclaim the space
- Whether going dark triggers any co-tenancy remedies for neighboring tenants
Where landlords get surprised: A dark tenant paying rent sounds fine — until a neighboring tenant exercises a co-tenancy termination right triggered by the dark store. The income looks stable right until it isn't.
For a deeper look at how these provisions interact, see our NNN dark clause guide.
---
5. Estoppel Requirements
Before closing on an NNN acquisition, buyers typically require tenant estoppels — certificates in which the tenant confirms the current state of the lease, any landlord defaults, and any side agreements not reflected in the written lease.
What to verify:
- Whether the lease gives the landlord the right to request an estoppel, and how quickly the tenant must respond (30 days is standard)
- Whether the lease makes delivery of an estoppel a condition on which a lender can rely — lenders will want this language if they're financing the acquisition
- Whether any side letters or amendments exist that aren't captured in the primary lease document
Where landlords get surprised: Tenants sometimes stall on estoppel delivery or return certificates with carve-outs and objections. Understanding your contractual leverage to compel timely delivery is important before you're deep into the closing timeline.
---
6. Lease Expiration and Renewal Options
The terminal value of an NNN property depends heavily on whether the tenant will stay. Renewal options — and the rent structure that comes with them — determine how much optionality the tenant holds versus the landlord.
What to pull from the lease:
- Lease expiration date and any extension options
- Notice requirements for option exercise — most options require 6 to 12 months advance notice before the term expires; a tenant who misses this deadline typically loses the right entirely
- The rent formula for option periods: fixed rent, fair market value rent, or CPI-adjusted rent
- Whether options are personal to the original tenant or can be transferred with an assignment
Where landlords get surprised: Renewal options priced at below-market rates can significantly limit your ability to reset economics at renewal. When options are priced at "fair market value," understand how the determination process works — if the lease allows the tenant to challenge the value, you may be in arbitration before you see renewal rent.
---
7. Personal Guarantee Validity
If the lease is backed by a personal guarantee from the operator or an entity guarantee from the parent company, you need to know what that guarantee is actually worth.
What to verify:
- Whether a guarantee exists and who the guarantor is
- Whether the guarantee is absolute or limited (limited guarantees cap the guarantor's exposure by amount or time)
- Whether the guarantee can survive an assignment — if the original tenant assigns the lease to a new entity, does the guarantee follow?
- The financial standing of the guarantor today, not just at lease inception
Where landlords get surprised: Guarantees signed by operating entities are only as strong as the operating entity. A franchisee guarantee backed by a single-purpose LLC may have limited practical value. Understand whether you're relying on a creditworthy guarantor before you underwrite the guarantee as meaningful protection.
For a detailed look at personal guarantee structures in NNN leases, see our personal guarantee guide.
---
8. Assignment and Subletting Rights
When you acquire a property, you inherit the tenant's right to assign or sublet. It's worth knowing exactly what those rights look like before you close.
What to pull from the lease:
- Whether the tenant needs landlord consent for any assignment or subletting
- Whether consent can be reasonably withheld, or whether it must be given in any case (some leases require the landlord to approve qualified assignees automatically)
- Whether the tenant retains liability after an assignment or is released upon landlord consent
- What happens to rent in the event of a sublease — does the landlord share in any profit subletting above the base rent?
---
The Pre-Close Verification Process
Most of what's listed above can be pulled from the lease document itself. Some of it requires verification against third-party sources:
- Estoppels confirm the tenant's view of the lease
- Title search surfaces any recorded easements, restrictions, or encumbrances that affect CAM or operations
- Current rent roll confirms that scheduled rent is actually being received
- Operating expense history gives you a baseline for whether CAM charges have been running at expected levels versus what the lease permits
The goal isn't to find a reason not to buy. It's to understand exactly what you're acquiring — and to price accordingly.
> PigJet is built to track exactly the data points that surface in a lease review: escalation schedules, CAM caps, co-tenancy thresholds, renewal option windows, and critical date alerts. If you're managing acquired NNN properties after closing, a lease management system designed for NNN economics makes tracking these moving parts significantly more reliable than doing it in a spreadsheet. Learn more about PigJet.
---
The Bottom Line
NNN acquisitions reward buyers who do thorough lease review before closing. The checklist above won't substitute for a qualified commercial real estate attorney reviewing the actual documents — but it gives you a working framework for what needs scrutiny and what questions to bring to that review.
The landlords who get surprised after closing are almost always the ones who read the rent schedule, liked the number, and moved on. The provisions that matter most — CAM caps, co-tenancy triggers, dark clause language, renewal option pricing — don't announce themselves. They sit quietly until market conditions or tenant decisions make them relevant.
Read the whole lease.