Chapter 4 · NNN true-up

What is an NNN true-up?

Guide · August 2026 · Not legal or accounting advice

A triple-net (NNN) lease usually passes through more than common-area maintenance. The year-end true-up is the same idea as a CAM true-up: monthly estimates versus the actual recoverable pool. The difference is what sits in that pool.

What NNN means in practice

“Triple-net” is a shorthand for a rent structure in which the tenant pays base rent plus a share of the landlord’s operating costs, real-estate taxes, and insurance — the three nets. CAM is often used as shorthand for the whole reconciliation, including tax and insurance, because the monthly invoice is one line and the year-end packet is one envelope.

In a typical U.S. retail or industrial NNN lease, that share is:

• Operating expenses / CAM — common-area utilities, janitorial, landscaping, repairs, security, snow, and similar building or park costs the lease calls recoverable. On a single-tenant industrial building the CAM list can be thin (access roads, detention, signage) because the tenant maintains its own premises.
• Real-estate taxes — the property-tax bill on the land and building, allocated by the lease’s share, sometimes plus assessments. Not the landlord’s income tax.
• Insurance — property and sometimes liability, terrorism, or flood premiums the landlord places on the building. Your own contents and liability policies are usually separate.

Landlords often bill one monthly “NNN” or “additional rent” estimate that lumps those three. The year-end statement may still show one settlement number, or three. Either way, the settlement is: your share of the recoverable pool minus what you already paid.

Not every “NNN” lease is identical. Some are NN — taxes and insurance only, with operating costs in base rent or handled another way. Some are modified gross with a base-year stop and a cover that still says NNN. Some cap CAM but not taxes. Some require the tenant to carry the property policy and name the landlord, so there is no insurance pass-through at all. The label on the lease cover is not a formula. The definitions and exhibits are. For the wider category, see operating-expense pass-throughs.

Absolute-net and ground-lease structures go further — the tenant may take the tax bills and insurance directly, and CAM may not exist as a shared pool. If you pay the county and the carrier yourself, there is nothing to true-up except, perhaps, a small common-area or association charge. Do not force this chapter onto that lease.

Same settlement math

pro-rata × recoverable pool − estimates paid = true-up

What changes is the pool. Taxes and insurance are usually non-controllable: they are less likely to be grossed up, less likely to sit under an admin fee, and often excluded from a controllable cap. If the landlord’s packet folds tax and insurance into “CAM,” those distinctions get lost. Split the buckets if the statement lets you; ask for the split if it does not.

A positive NNN true-up means you owe additional pass-throughs. A negative number is a credit against future estimates (or, less often, a refund). There is no standard NNN percentage of sales or of rent that this site will invent.

When the statement gives you three columns, reconstruct three settlements — or one settlement with three inputs. A tax increase does not belong in a CAM cap conversation. An insurance audit additional premium does not belong in a janitorial gross-up. Adding the three true-ups should match the cover letter. If it does not, the difference is usually estimates (one lump subtracted from three pools) or a fee applied to the wrong base.

Taxes versus income tax

Real-estate / property tax is a levy on the land and improvements, paid to a county or city, often in arrears. On an NNN lease it is usually a pass-through. The backup is the tax bill, the parcel ID, and the allocation (whole parcel versus a lot-line split, a separately assessed pad, a personal-property line that is not real estate). Special assessments, business-improvement-district levies, and supplemental bills after a sale are lease questions: some forms include them, some treat a sale-triggered supplemental as the landlord’s.

Income tax, franchise tax, and gross-receipts tax on the landlord’s entity are taxes on the owner’s income or privilege of doing business. They are frequently excluded from operating expenses. Do not let a general-ledger line named “taxes” collapse the two. Property tax is usually recoverable; income tax is usually not. See exclusions.

Appeals and refunds: if the landlord contested the assessment and later received a refund, the lease will say whether the refund (net of reasonable contest costs, if allowed) credits the tenants who paid the original bill. A refund that sits in the landlord’s account while this year’s pool includes the full bill is a double picture of the same tax. Ask for the appeal status and any refunds received in the CAM year or after.

Transfer taxes, mortgage taxes, and taxes on a sale or refinance of the property are closer to the cost of owning or selling the asset than to the cost of operating it. Many exclusions exhibits name them. They do not become property tax because someone coded them to a tax account.

Insurance proceeds and self-insurance

The pass-through, when the lease allows it, is usually the premium the landlord paid for policies the lease requires or permits. The backup is the declarations page, the invoice or binder, and the allocation if one policy covers several properties. A blanket policy that also covers the landlord’s other assets should not drop the full premium into this building’s pool.

Proceeds. If a storm, a fire, or a claim produced an insurance payment, the repair cost should not also sit in CAM un-credited. Tenants look for the proceeds as a reduction of the pool, or for the repair to be capitalized and kept out of operating expenses. A deductible can be a closer question: some leases treat it as an operating expense, some do not, some cap it. Ask for the claim file summary and the credit.

Self-insurance and large retentions. A landlord that “self-insures” or carries a high self-insured retention may charge the pool a notional premium, or charge actual losses as they occur. Those are different economics. A notional premium wants a method (and a lease clause). Actual losses want a list, and they want to be tested against exclusions for capital, for landlord-caused events, and for amounts that should have been a claim on a policy the lease required the landlord to carry. This site will not tell you which structure is “standard.”

Tenant-placed insurance is usually not a pass-through. If you already pay a carrier for contents and liability, a second liability premium in NNN for the same exposure is a question. Landlord liability coverage for the common area is a different policy; the lease will say whether that premium is recoverable.

Lumped estimates, ownership changes, one tenant

The monthly “NNN” invoice is often one number. The year-end packet is where that number has to come apart. If you paid $32,000 in estimates (the homepage sample) and the statement subtracts that lump from a combined pool, you cannot tell whether tax was over-collected and CAM under-collected. Ask for the estimate split — even a three-line budget — so each bucket can settle on its own. A credit in tax and a charge in CAM can net to the same cover-letter total and still be two different conversations (a cap on CAM does not apply to tax; a gross-up does not apply to insurance).

Mid-year ownership changes scramble the tax picture. A sale can produce a supplemental assessment, a proration at closing, and a new parcel ID. The lease will say who bears a sale-triggered supplemental. Closing prorations are between buyer and seller; they should not, without a clause, become a second pass-through of a bill the outgoing owner already recovered. If the manager changed with the deed, estimates paid to the old manager still count as estimates paid. Match them to your records before you accept a shortfall that is really a missing month.

Single-tenant industrial and pad sites are a thinner version of the same math. There may be no shared janitorial. CAM can be a park association, a detention pond, and a monument sign. Tax and insurance then dominate the envelope. The denominator may be the whole building — your share is 100% — which makes pro-rata uninteresting and makes exclusions and recoveries the whole review. Multi-tenant retail is the opposite: GLA, vacant bays, and majors that do not participate matter as much as the tax bill. Use the asset-class notes in the reconciliation chapter; do not invent a recovery rate from the building type.

What people mean by “NNN true-up”

When people say “NNN true-up” they usually mean the year-end reconciliation of those pass-throughs — operating, tax, and insurance — against the monthly estimates. They do not usually mean a re-trade of base rent, a percentage-rent calculation, or a remeasurement of the premises. Those can happen in the same season. They are different clauses.

Brokers and property managers will also say “CAM true-up” when the envelope includes tax and insurance. Do not litigate the vocabulary. Identify the buckets, the share, and the estimates. If the letter is mostly operating expenses, start with what a CAM true-up is and how to read a CAM reconciliation. If taxes and insurance are in the same envelope, treat the calculator’s “actual CAM” (or the advanced split) as the recoverable pool the lease describes — not as a market rate. Costs you think should not be in the pool belong on the exclusions checklist.

OpEx, CAM recon, and the calculator

This chapter is the label. The spine is still CAM reconciliation: calendar the objection window, test the denominator, build the pool, apply gross-up / fee / cap only where the lease applies them, subtract estimates. The OpEx chapter is the structure (gross, modified, base-year, stop, NNN). Use both.

Type the landlord’s numbers into the free calculator and see the headline true-up on the page. Put tax and insurance in the advanced non-controllable box when you have the split. The optional $79 landlord packet is a two-page worksheet — line-item math plus a blank exclusion checklist — not an audit and not a subscription.