PTB charges in a lease are pass-through charges: operating costs the landlord pays to run the building and then bills back to you on top of base rent. In a commercial lease, that typically covers property taxes, building insurance, common area maintenance, shared utilities, and a management fee. Your share is calculated from the size of your space relative to the building, adjusted each year through a reconciliation against the landlord’s actual costs. Getting these numbers wrong is one of the most common ways commercial tenants overpay, sometimes by thousands of dollars a year.
Most leases classify pass-through charges as “additional rent.” That label matters: if you stop paying them, the landlord can pursue the same default remedies as unpaid base rent, including summary eviction. It also means the lease itself controls almost everything about how PTB works. There is no general statute that governs commercial pass-throughs the way consumer laws regulate residential rentals, so the language you signed dictates which costs qualify, how they are allocated, when the landlord has to send a reconciliation, and how long you have to challenge it.
What Costs Get Passed Through
The specific line items depend on your lease, but most commercial leases draw from the same core categories.
- Common area maintenance (CAM): Upkeep of shared spaces — lobbies, hallways, parking areas, landscaping, elevators, snow removal, cleaning.
- Property taxes: The building’s real estate tax bill, divided among tenants. Because the assessment is set by the local government, this is usually treated as uncontrollable and passed through without a cap.
- Building insurance: Premiums for the landlord’s property and liability coverage on the building and common areas, typically passed through at actual cost.
- Shared utilities: Water, sewage, electricity, and gas for common areas. If your space is not separately metered, your share of building-wide utilities may also be included.
- Management fees: An administrative charge, usually a percentage of total operating expenses or collected rent. Industry practice puts this somewhere between 4% and 12% depending on the property type and market. The fee inflates proportionally as other costs rise, so it is worth tracking.
Leases often split these costs into controllable and uncontrollable expenses. Controllable costs are the ones the landlord can influence through vendor choices: janitorial, security, landscaping. These are where a tenant has leverage to negotiate an annual cap, often around 5% compounding per year. Uncontrollable costs — taxes, insurance, utility rates set by public commissions — generally pass through at actual cost with no cap because the landlord cannot control them. If your lease lumps everything together with no cap, a single property tax reassessment can spike your bill overnight.
Routine pass-throughs are supposed to cover day-to-day operating costs, not big capital projects. Many leases, however, include an amortization clause that lets the landlord spread certain capital costs — often improvements required by a new law or improvements that reduce operating expenses — over the asset’s useful life, passing through only the annual amortization amount rather than the full cost in one year.
How Your Share Is Calculated
Your bill starts with a simple ratio: your rentable square footage divided by the building’s total rentable area. Lease 2,000 square feet in a 20,000-square-foot building and your pro-rata share is 10%. That percentage applies to the qualifying expenses to produce your portion.
What happens next depends on which method your lease uses to set the starting point.
Base Year
A base year lease uses the building’s operating expenses during the first year of your lease as the baseline. You pay only for increases above that baseline in later years. If base year taxes were $50,000 and current year taxes are $60,000, the $10,000 increase is what gets allocated. At a 10% pro-rata share, you would owe $1,000 for the tax pass-through that year. The base year method is common in modified gross leases and protects you early in the term. The risk builds later, as costs compound and the gap between the base year and current year widens.
Expense Stop
An expense stop works like a fixed deductible stated in the lease, often as a dollar amount per square foot. The landlord absorbs operating expenses up to that threshold, and you pay your pro-rata share of anything above it. Unlike a base year, the stop does not change from year to year. Expense stops are especially common in new buildings that lack operating cost history. The negotiation centers on setting the stop at a level that reflects the building’s actual costs.
Gross-Up Provisions
A gross-up clause adjusts variable operating expenses upward to reflect what they would have been if the building were close to full occupancy, typically 95% to 100%. This matters most when the building is half-empty during your base year. Without a gross-up, your base year captures artificially low cleaning and utility costs. When the building fills up later, those costs jump and the entire increase gets passed to you. Only variable expenses tied to occupancy get grossed up; fixed costs like taxes and insurance are unaffected.
How Your Lease Type Changes Your Exposure
Not every commercial lease handles pass-throughs the same way. The structure determines how much of the building’s operating cost ever reaches you.
- Triple net (NNN) lease: You pay base rent plus your proportionate share of operating expenses, property taxes, and insurance. Common in single-tenant and retail properties, and the structure that demands the closest scrutiny of every line item.
- Modified gross lease: You pay a higher base rent that absorbs some operating costs, with increases above a base year or expense stop passed through. Common in multi-tenant office buildings.
- Absolute net lease: You take on full financial responsibility, including structural repairs and roof replacement. Typically used in single-tenant properties where the tenant operates almost like an owner.
- Full-service gross lease: The landlord bundles operating expenses into the rent. True gross leases have no pass-throughs, but many include an expense stop that shifts costs to you once expenses exceed a set threshold.
Knowing which structure you signed sets your baseline exposure before you look at a single line item.
The Annual Reconciliation
Most leases require estimated monthly payments toward pass-throughs throughout the year. After year-end, the landlord issues a reconciliation statement comparing your estimated payments against actual building expenses. If actual costs exceeded your estimates, you owe the difference. If you overpaid, you get a credit against future charges.
This statement is the single most important document in pass-through billing. A proper reconciliation shows total building expenses by category, your pro-rata share percentage, the total amount due, and the amount already collected through monthly estimates. Review it carefully. Errors in square footage, expenses that should have been excluded, and misclassified capital costs are among the most common problems tenants find.
Your lease should specify when the landlord must deliver the statement — often within 90 to 120 days after calendar year-end — and how long you have to review and dispute it. If those deadlines are not in the lease, you have less leverage when a statement arrives late or contains stale numbers.
Your Right to Audit
An audit right is the most powerful tool you have for verifying PTB charges. The provision lets you, or an accountant you hire, examine the landlord’s actual invoices, tax assessments, insurance statements, utility bills, and internal accounting records to confirm the reconciliation is accurate.
A well-drafted audit clause covers a few practical details:
- Deadline to request: Commonly 30 to 90 days after you receive the reconciliation. Miss the window and you typically waive the right for that year.
- Who pays: Tenants usually cover audit costs, but many leases shift the cost to the landlord if the audit reveals an overcharge above a set threshold, often 3% to 5%.
- Scope of records: Vendor contracts, invoices, tax assessments, insurance policies, utility bills, and internal allocation reports.
- Confidentiality: Landlords often require that findings stay confidential, particularly in multi-tenant buildings.
If your lease has no audit right, you can still ask for backup documentation, but the landlord has no obligation to provide it. This is one of those provisions that costs nothing to negotiate at signing and becomes invaluable if charges start climbing faster than expected. Tenants who never audit tend to overpay; landlords know who checks the math.
Charges That Should Not Appear on Your Statement
Even in a triple net lease, not every cost the landlord incurs qualifies as a pass-through. Watch for these on your reconciliation:
- Unamortized capital expenditures: The full cost of a new roof or parking lot resurfacing should not land in a single year unless the lease specifically allows it.
- Leasing costs: Brokerage commissions, advertising for vacant space, and tenant improvement allowances benefit the landlord, not existing tenants.
- Costs for other tenants: Repairs or build-outs for a specific tenant’s space should not be allocated across the building.
- Pre-existing code violations: If a code violation existed when you signed the lease, correcting it belongs to the landlord.
- Landlord’s income taxes: Property taxes on the building are standard; the landlord’s own income taxes are not.
- Depreciation: An accounting concept, not a cash expense, and not a pass-through.
Any of these on your statement is a strong signal that a full audit is worth the cost.
The Lease Language Controls Everything
Because pass-through billing is contractual, almost every protection a tenant has — caps on controllable expenses, gross-up requirements, audit rights, reconciliation deadlines, exclusions for capital and leasing costs — has to be written into the lease before you sign. Once the lease is executed, the PTB provisions are locked in for the term. The time to shape what will appear on your reconciliation statement years from now is during the negotiation, not when the first unexpected bill arrives.