The direct answer
An expense stop or base-year provision allocates commercial operating expenses between landlord and tenant. An expense stop is a specified threshold above which a tenant reimburses eligible expenses; a base year uses an agreed historical expense level as the comparison point, adjusted according to the lease.
Define reimbursable categories
Taxes, insurance, utilities and common-area expenses may be treated differently. The lease governs exclusions, caps, gross-up adjustments and reconciliation.
To apply the approach to an editable scenario, use the NNN Lease Calculator. For the neighboring question, explore Commercial Rent Calculator.
Calculate increases above the benchmark
For an illustrative $8 per rentable square foot base-year benchmark and $10 current eligible cost, the $2 increase may be passed through according to the tenant share.
Forecast cost escalations
Tax reassessments, utilities and insurance changes can materially alter landlord net income and tenant occupancy costs.
Worked example
A tenant occupying 5,000 rentable square feet with a $2 per-square-foot eligible expense increase might reimburse $10,000 annually, assuming full pass-through with no exclusions or caps.
Common mistakes and limitations
Do not treat an expense stop as a fixed gross-rent increase; individual lease definitions and exclusions matter.
Actual NNN leases define recoverable expenses, audit rights, caps and reconciliations contractually.
Frequently asked questions
Is an expense stop the same as NNN rent?
No. Both can shift expenses, but the allocation mechanism is different.
Does the base year always stay fixed?
Not necessarily. The lease may include special resets or negotiated adjustments.
Sources and further reading
The article’s examples are illustrative arithmetic. The references below provide context for operating, valuation or transaction concepts; they do not endorse the assumptions or the calculator.
- Office of the Comptroller of the Currency — Comptroller's Handbook — Commercial Real Estate LendingNOI, direct capitalization, cap-rate valuation and DCF concepts for commercial real estate.
- Appraisal Institute — Basic Formulas — Income CapitalizationIncome/cap-rate/value relationships, gross income multiplier and debt-coverage formula references.
Read our editorial policy for the scope of these educational methods.