Gross-up provisions require variable operating expenses to be adjusted to a specified occupancy level. Here's the exact math — with a worked example at 65% occupancy.
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Find My OverchargesSee a sample report firstThe gross-up provision is one of the more technically demanding clauses in a commercial lease. It requires you to understand what the landlord is adjusting, why, and whether the math is correct — because errors in gross-up calculations are common and are almost always in the landlord's favor.
40% of CAM reconciliations contain material errors (Tango Analytics/PredictAP, 2023)
This article works through a complete gross-up calculation from scratch, at 65% occupancy, and identifies the four violations CAMAudit's Rule 5 is built to detect.
Gross-up provisions exist because some operating expenses are variable — they scale with building occupancy. Janitorial costs are higher when more tenants occupy more space. Utility consumption increases as occupied floors run HVAC, lighting, and equipment. Trash removal increases with tenant density.
In a low-occupancy year, these variable costs are genuinely lower than they would be at full occupancy. Without a gross-up provision, each occupied tenant would absorb a smaller absolute CAM charge — which sounds favorable — but that calculation is misleading: the tenant is paying for a partially occupied building's variable costs as if those lower costs reflect the "real" cost of operating their space.
The gross-up provision corrects for this by asking: what would these variable costs be if the building were at the target occupancy level? It then calculates the tenant's share based on that hypothetical full-occupancy cost rather than the depressed actual cost.
The tenant pays the same share they would pay in a fully occupied building. The landlord doesn't profit from vacancy: it absorbs the difference between the grossed-up costs and the actual costs.
This is a legitimate and standard provision. The problems arise in execution.
Every correct gross-up calculation follows two steps. Skipping either step or applying the formula to the wrong inputs produces an error.
Step 1: Identify which expenses are variable and which are fixed.
Fixed expenses — property taxes, insurance premiums, management fees on a percentage-of-rent basis — do not change with occupancy. A building's property tax assessment is the same whether it is 40% or 100% occupied. Applying a gross-up factor to fixed costs inflates them beyond what a fully occupied building would actually incur, creating an overcharge.
Variable expenses — janitorial, utilities, landscaping, certain maintenance contracts — scale with occupancy. These are the only expenses that should be grossed up.
Step 2: Apply the gross-up factor to variable expenses only.
The gross-up factor is:
Gross-Up Factor = Target Occupancy % ÷ Actual Occupancy %
The grossed-up variable expense total is:
Grossed-Up Variable = Actual Variable × Gross-Up Factor
The total CAM pool used for pro-rata share calculations is:
Total Grossed-Up Pool = Grossed-Up Variable + Actual Fixed
Building: 85,000 sq ft suburban office park Lease Year: 2021 Actual Occupancy: 65% (55,250 sq ft occupied) Gross-Up Target: 95% (as specified in lease) Tenant: 7,140 sq ft — 8.4% of total building area
Variable Expenses (eligible for gross-up):
| Line Item | Actual Cost |
|---|---|
| Janitorial / cleaning | $180,000 |
| Building utilities (electric, gas, water) | $340,000 |
| HVAC maintenance and service | $95,000 |
| Landscaping and exterior maintenance | $48,000 |
| Total Variable | $663,000 |
Fixed Expenses (not eligible for gross-up):
| Line Item | Actual Cost |
|---|---|
| Property taxes | $280,000 |
| Casualty and liability insurance | $72,000 |
| Total Fixed | $352,000 |
Total Actual Operating Costs: $1,015,000
Gross-Up Factor = 95% ÷ 65% = 1.4615
Grossed-Up Variable = $663,000 × 1.4615 = $968,975
Total Grossed-Up Pool = $968,975 (variable) + $352,000 (fixed) = $1,320,975
Tenant occupies 8.4% of the building. Under the gross-up provision:
Tenant's grossed-up CAM charge = $1,320,975 × 8.4% = $110,962
For comparison, the tenant's share without any gross-up:
Tenant's non-grossed-up charge = $1,015,000 × 8.4% = $85,260
The gross-up provision increases the tenant's charge by $25,702 in this year. This is the legitimate and correct application of the provision — the tenant pays as if the building were 95% occupied, which is what their lease requires.
If the landlord incorrectly applied the gross-up factor to the total operating costs (including fixed):
Incorrectly grossed-up pool = $1,015,000 × 1.4615 = $1,483,423
Tenant's incorrect charge = $1,483,423 × 8.4% = $124,608
This overstates the tenant's charge by:
$124,608 - $110,962 = $13,646
That overcharge — $13,646 — comes entirely from applying the gross-up factor to $352,000 of fixed costs that should not have been grossed up. The landlord collected a gross-up premium on taxes and insurance that do not increase with occupancy. This is the most common gross-up violation CAMAudit encounters.
CAMAudit's Rule 5 (Gross-Up Violation) is structured as an advisory finding because confirming the violation requires occupancy data the tenant may need to separately request. The rule identifies the pattern; the tenant quantifies it.
The most prevalent error. Property taxes, insurance premiums, and other fixed costs are included in the grossed-up base alongside variable costs. Because the gross-up factor is always greater than 1.0 when actual occupancy is below target, applying it to fixed costs inflates them. The landlord charges tenants for a higher tax or insurance bill than was actually incurred — a bill that would not have been any higher in a fully occupied building.
How to detect: Request the gross-up calculation worksheet. Identify which line items the landlord included in the variable pool. Any line item that does not vary with building occupancy should not appear in the grossed-up base.
The gross-up factor's denominator is actual occupancy. If the landlord understates actual occupancy, the factor increases, producing a larger grossed-up pool and a higher tenant charge.
Occupancy can be measured as a percentage of leasable area occupied (the most common definition) or as a percentage of leased-up area (including tenants who have signed leases but not yet taken occupancy). The lease should specify. Using leased-up area instead of actually occupied area will generally produce a higher occupancy percentage (lower gross-up factor, smaller charge) — but using an incorrectly low occupancy figure does the opposite.
How to detect: Request the occupancy calculation underlying the gross-up. Verify against rent rolls, which show all occupied tenants and their square footage for each month of the year. Annual gross-up calculations should use average occupancy across the 12 months, not spot occupancy on a single date.
The gross-up provision is a protection against low occupancy. If actual occupancy is already above the target — 95% actual against a 95% target — the gross-up factor is exactly 1.0 and gross-up has no effect. If actual occupancy exceeds the target — 97% actual against a 95% target — the gross-up factor is less than 1.0 and grossing up would reduce the variable expense pool below actual (which is the wrong direction).
In years when actual occupancy exceeds the gross-up target, no gross-up adjustment should be applied. Landlords occasionally apply the provision mechanically without checking whether the trigger condition (below-target occupancy) is actually met.
How to detect: Verify actual occupancy for the reconciliation year. If it meets or exceeds the target stated in the lease, challenge any gross-up adjustment.
Leases specify the gross-up target — typically 90%, 95%, or "full occupancy." Some landlords calculate gross-up at a different target than the lease specifies. A landlord who uses 100% as the target instead of the lease-specified 95% would increase the gross-up factor from 1.4615 to 1.5385 (at 65% actual occupancy) — increasing the grossed-up variable pool by an additional $49,000 in the example above.
How to detect: Verify the target percentage in the gross-up calculation against the lease. The lease definition controls; the landlord's worksheet is subordinate to the lease.
Rule 5 is advisory because CAMAudit does not have the occupancy data independently — it reads the lease (which contains the gross-up provision and target) and the reconciliation statement (which may or may not itemize the gross-up calculation). When the rule fires, it identifies that a gross-up provision exists and flags indicators of possible misapplication.
Quantifying the overcharge requires actual occupancy data. The most efficient request:
"Pursuant to Section [X.X] of the Lease (Audit Rights), please provide: (1) the gross-up calculation worksheet for the [year] reconciliation, including the enumeration of expenses treated as variable and the actual occupancy percentage used; (2) monthly rent rolls for [year] showing occupied square footage by tenant."
With those documents, you can run the correct calculation and compare it to what the landlord applied.
Gross-up provisions are often discussed from the perspective of whether they harm tenants (by increasing charges in low-occupancy years). That framing is incomplete.
In a correctly applied gross-up, tenants pay what they would pay in a fully occupied building — no more. The tenant is indifferent to whether the building is 65% or 95% occupied, because their charge is always computed as if it were 95% occupied.
The tenant's interests are harmed only when the gross-up is applied incorrectly. The four violations above all produce charges higher than a correctly applied provision would generate. In a year when the building is genuinely 65% occupied, the tenant should verify the gross-up with the same care as any other line item.
"After testing reconciliation samples from published audit cases through CAMAudit, the most reliable gross-up error was applying the factor to property taxes and insurance — fixed-cost items that do not scale with occupancy. The landlord ran the same gross-up formula across the entire operating cost pool without distinguishing variable from fixed." — Angel Campa, Founder of CAMAudit
This classification guides which expenses enter the gross-up calculation. The list is not exhaustive; lease definitions may expand or restrict it.
Typically Variable (eligible for gross-up):
Typically Fixed (not eligible for gross-up):
Boundary Cases (require lease interpretation):
A correctly applied gross-up increases the CAM pool; an incorrectly applied gross-up inflates it. In both cases, the tenant's pro-rata share percentage is applied to the pool to determine their charge.
This means pro-rata share errors and gross-up errors compound each other. A tenant with a 10% pro-rata share (itself potentially erroneous — see BOMA Measurement Standards and CAM) applied to a $13,646-inflated gross-up pool pays an additional $1,365 in pro-rata share errors on top of the gross-up error.
When CAMAudit runs Rule 4 (Pro-Rata Share) and Rule 5 (Gross-Up) together, it can detect this compounding — the total charged exceeds what the stated pro-rata percentage applied to a correctly grossed-up pool would produce.
Q: How do I know if my building has a gross-up provision?
Search your lease for "gross up," "grossed up," or "adjusted to [X]% occupancy." The provision typically appears in the CAM or Operating Expenses definition section. It will specify a target occupancy level (usually 90%, 95%, or "full occupancy") and state that variable operating expenses shall be adjusted to that level. If no such provision exists, gross-up does not apply and any upward adjustment of operating costs for low occupancy is impermissible.
Q: My lease says gross-up to "full occupancy." Does that mean 100%?
"Full occupancy" is sometimes defined as 100% and sometimes as 95% (treating 95% as effectively full). Check whether your lease defines "full occupancy" elsewhere. If it does not, 100% is the most natural reading — but note that 100% occupancy is rarely actually achieved, making the gross-up factor higher than a 95% target would produce. A 95% target is more favorable to tenants and is the more common market standard for the gross-up target.
Q: Can a landlord use different occupancy percentages for different expense categories?
Theoretically yes, if certain variable costs genuinely scale differently with occupancy. For example, elevator maintenance might be contracted at a flat monthly fee and thus not variable at all, while janitorial scales linearly with occupied floors. In practice, most landlords use a single occupancy percentage for the entire variable pool. If a landlord uses a different occupancy figure for different line items without a lease basis for doing so, that warrants scrutiny.
Q: If the building was 65% occupied for part of the year and 80% occupied for the rest, which occupancy percentage applies?
The lease should specify whether occupancy is measured as average annual occupancy, minimum occupancy during the year, or occupancy at some specific point. If it doesn't specify, the most defensible approach is average annual occupancy — the average of monthly occupancy percentages weighted by the number of days in each month. This prevents landlords from using the lowest occupancy month to maximize the gross-up factor applied to the full annual expense pool.