How to Calculate CAM Floor (Minimum Guarantee) Charges
The formula and process for billing CAM floors — minimum charges that apply when actual pro-rata share falls below the floor amount.
A CAM floor (also called a CAM minimum guarantee) is a lease provision that establishes a minimum amount a tenant must pay in CAM charges regardless of how low actual expenses turn out to be. Floors protect landlords' income streams in periods of low operating expenses or high vacancy and are common in ground-floor retail leases, anchor tenant agreements, and sale-leaseback transactions where the landlord needs predictable minimum income. Floors are less common than caps but can create significant overbilling disputes when landlords charge a floor in years when the actual expenses would have resulted in a lower charge. Importantly, a floor does not eliminate the annual reconciliation — the landlord must still calculate the actual pro-rata share and bill the greater of the actual share or the floor.
Formula
Annual CAM Billing = MAX(Actual Pro-Rata Share, Floor Amount)
Variables
| Name | Symbol | Definition | Example |
|---|---|---|---|
| Actual Pro-Rata Share | APRS | The tenant's calculated pro-rata share of actual CAM expenses for the reconciliation year, calculated per the standard proration methodology (and adjusted for gross-up, caps on controllable items, etc.). | $72,000 actual annual CAM based on tenant's 10% share of $720,000 total pool |
| Floor Amount | FA | The minimum annual CAM amount the tenant is obligated to pay, as specified in the lease. May be expressed as a fixed dollar amount, a per-SF rate multiplied by tenant SF, or a percentage of the prior year amount. | $8.00/SF × 10,000 SF = $80,000 minimum annual CAM floor |
| Floor Basis | FB | How the floor amount is defined in the lease: per-SF rate (most common in retail), fixed dollar amount, or a percentage of prior year actual. Determines how the floor scales if tenant SF changes. | $8.00 per RSF per year, applied to 10,000 RSF = $80,000 floor |
Step-by-Step Process (4 steps)
Identify the Floor Clause and Calculate the Floor Amount
Review the lease's CAM provision for any minimum guarantee, floor, or expense stop language. Calculate the floor amount for the current year using the formula defined in the lease (per-SF rate × tenant RSF, or the fixed dollar amount, or the prior year percentage). Confirm whether the floor adjusts annually (e.g., increases by CPI) or is fixed.
Example:
Lease states: 'Tenant's CAM charges shall not be less than $8.00 per RSF per lease year.' Floor = $8.00 × 10,000 SF = $80,000.
Calculate Actual Pro-Rata Share
Complete the standard annual CAM reconciliation to determine the tenant's actual pro-rata share of actual operating expenses, after all adjustments (exclusions, gross-up if applicable, cap on controllable items if applicable).
Example:
Total CAM pool $720,000. Tenant share 10%. Actual pro-rata share = $72,000.
Compare Actual Share to Floor Amount
Compare the actual pro-rata share to the floor amount. The tenant is billed the greater of the two. Document both amounts in the reconciliation workpaper so the tenant can verify the calculation.
Billing = MAX(Actual Pro-Rata Share, Floor Amount)
Example:
MAX($72,000, $80,000) = $80,000. Tenant is billed at the floor.
Calculate and Bill Any True-Up
Compare the floor billing to any monthly estimates already collected. If monthly estimates were based on estimated actual share ($72,000 / 12 = $6,000/month), but the floor applies ($80,000 / 12 = $6,667/month), the landlord is owed $8,000 for the year (the difference between floor and actual estimates paid). Issue a reconciliation statement showing the floor calculation and resulting balance due.
Example:
Monthly estimates paid at $6,000/month × 12 = $72,000. Floor billing = $80,000. Balance due = $8,000.
Worked Example
Scenario
Street-level retail tenant occupying 10,000 SF. Lease includes a CAM floor of $8.00/SF/year. Actual 2025 CAM pool was lower than expected due to reduced landscaping and deferred maintenance. Tenant pays monthly estimates of $6,000/month.
Inputs
| Variable | Value |
|---|---|
| Tenant RSF | 10,000 SF |
| CAM Floor Rate | $8.00/SF/year |
| Floor Amount | $80,000 |
| Total CAM Pool (actual) | $720,000 |
| Tenant Pro-Rata Share | 10% |
| Actual CAM Share | $72,000 |
| Monthly Estimates Paid | $6,000/month × 12 = $72,000 |
Calculation
Step 1: Floor = $8.00 × 10,000 = $80,000 Step 2: Actual share = $720,000 × 10% = $72,000 Step 3: Billing = MAX($72,000, $80,000) = $80,000 Step 4: Balance due = $80,000 − $72,000 = $8,000
Result:
Tenant is billed $80,000 for the year ($8.00/SF), even though actual pro-rata share was only $72,000 ($7.20/SF). The floor adds $8,000 to the tenant's obligation. Balance due at reconciliation: $8,000.
Common Mistakes
Charging a floor and also attempting to recover actual expenses above the floor — the floor is a minimum, not an additional charge on top of actual expenses.
Failing to conduct the annual reconciliation when a floor applies, and simply billing the floor amount without calculating actual expenses — this deprives the landlord of recovery above the floor in high-expense years.
Confusing a CAM floor with a CAM cap — a floor is a minimum (MAX function), a cap is a maximum (MIN function). Both can exist in the same lease simultaneously.
Not adjusting the floor for tenant SF changes when the lease defines the floor on a per-SF basis and the tenant expands or contracts.
Setting monthly estimates at the floor rate even when actual expenses are expected to exceed the floor, then issuing a large year-end true-up to the tenant.
Applying the floor to gross CAM before deducting the tenant's actual share — the floor comparison must be made after calculating the actual pro-rata share.
When to Use This Calculation
- When a tenant's lease contains a CAM floor, minimum guarantee, or expense stop provision, in every annual reconciliation for that tenant.
- When reviewing a CAM reconciliation as a tenant to verify whether the floor provision was applied correctly and whether actual expenses actually fell below the floor.
- When underwriting a property acquisition to project minimum CAM recovery per tenant based on floor provisions in existing leases.
- When negotiating a new lease to understand the financial impact of proposed floor provisions at various occupancy and expense levels.
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