How to calculate CAM caps and exclusions

Start with what's actually recoverable

Before caps or exclusions enter the picture, every CAM-eligible expense needs a yes-or-no answer: does the lease allow this category to be passed through to tenants at all? Anything that isn't recoverable goes to HOUSE—the owner's own cost, tracked but never billed.

Caps and exclusions only apply on top of that recoverable base. Getting the base wrong makes every downstream calculation wrong too, no matter how carefully the cap math is applied.

What a controllable-expense cap actually limits

Most caps apply only to “controllable” expenses—landscaping, cleaning, general repairs, administrative fees—not to the whole CAM bill. Real estate taxes, insurance, utilities, and snow removal are usually carved out as “uncontrollable” and pass through in full, uncapped.

The logic is straightforward once you see it: a landlord has some ability to shop for a cheaper landscaping vendor, so a tenant can reasonably ask that category to be capped. A landlord has no ability to negotiate the county's tax assessment, so leases rarely try to cap it.

Cumulative vs. compounding caps—the math that trips people up

Lease drafters use different terms for this, but the two versions you'll run into most often work differently enough to change what a tenant owes by thousands of dollars over a term.

A compounding cap carries the CAP itself forward: this year's ceiling is last year's ceiling times (1 + the cap percentage), regardless of what was actually spent. A cumulative (sometimes called non-compounding) cap resets its base to actual controllable spending each year, then limits only that year's increase—so a year where actual expenses came in under the prior cap lowers the base for every year afterward.

• Compounding: this year's cap = last year's CAP × (1 + cap%)
• Cumulative: this year's cap = last year's ACTUAL controllable spend × (1 + cap%)
• A compounding cap is more predictable for the owner; a cumulative cap is more favorable to the tenant whenever actual spending runs below the cap

Common exclusions, and why they each exist

Exclusions carve specific costs out of CAM even when the category would otherwise be recoverable. Most exist for a clear reason once you know it.

• Capital expenditures (roof, HVAC replacement, parking lot resurfacing)—often excluded entirely, or allowed only as an amortized portion over the item's useful life
• Leasing commissions and tenant-improvement costs—these benefit the owner's re-leasing effort, not the existing tenants
• An administrative or management fee cap—many leases cap the admin fee itself at a stated percentage of total CAM, separately from the controllable-expense cap
• Costs to cure a code violation that predates the lease—the owner's own pre-existing obligation, not a shared operating cost
• Fines or penalties from the owner's own negligence

A worked example

Say a tenant's controllable share was capped at $11,400 last year (actual spending came in at $11,000), the lease uses a 5% cumulative cap, and this year's uncapped pro-rata share works out to $12,000.

Cumulative cap: this year's ceiling is $11,000 × 1.05 = $11,550—lower than the $12,000 uncapped share, so the tenant owes $11,550, and the excess never gets billed or carried forward. Compounding cap: this year's ceiling is $11,400 × 1.05 = $11,970—still below $12,000, so the tenant owes $11,970 instead. Same lease term, same year, a $420 difference, purely from which version of “cap” the lease actually specifies.

What still needs a person

Whether a specific expense falls inside or outside an exclusion is sometimes a genuine judgment call—a repair that's really a capital improvement in disguise, for instance. Read the exact exclusion language, and when it's ambiguous, that's a conversation with an attorney or an experienced CAM consultant, not a formula.