The structural setup
Industrial leases are typically NNN — net of taxes, insurance, and CAM (common area maintenance). Each year the landlord issues a reconciliation showing actual expenses incurred during the prior period and reconciling that to the estimates you paid monthly. If actuals came in higher than estimates, you owe a balance. If lower, you get a credit.
The reconciliation arrives as a one- or two-page summary with a single bottom-line number. The detail behind that number lives in supporting schedules most tenants never request. The overcharges hide there.
None of what follows is a claim about landlord ethics. Most landlords' CAM reconciliations contain errors that benefit the landlord because the system is structured that way — not because anyone is trying to cheat you. The errors get caught when tenants check. They don't get caught when tenants don't.
Capital expenses reclassified as operating
This is the largest single category of CAM overcharges. Operating expenses (passed through to tenants) cover routine maintenance and repair: HVAC service, parking lot striping, landscape mowing. Capital expenses (almost always not passed through, or amortized over the useful life if they are) cover replacements and improvements: new roof, parking lot resurfacing, HVAC replacement.
The line between maintenance and capital is fuzzy by design. A $40,000 parking lot patching job is operating. A $400,000 parking lot resurface is capital. Landlords occasionally book the resurface as operating because the lease language allows "routine maintenance" without defining "routine." Or they amortize the capital expense over 3 years instead of the 15-year useful life.
What to check: Any single line item in CAM exceeding $25,000 should have a supporting invoice. Pull it. If it's a replacement or improvement (new equipment, resurfacing, new roof sections), it's capital. Either it shouldn't be passed through at all, or it should be amortized over its useful life.
Management fees stacked twice
Most leases allow the landlord to charge a property management fee — typically 3–5% of gross operating expenses or gross rent. Most leases also allow the landlord to pass through "professional services" used in property management.
The double-count happens when both are present and the management company is an affiliate of the landlord. The landlord's management entity bills 4% for property management. Then the same entity bills hourly for "professional services" that are part of standard property management — leasing coordination, vendor management, financial reporting.
What to check: Compare the management fee line to any other line categorized as "professional," "administrative," or "asset management." If the same affiliated entity appears in both, you're paying twice for the same service. Most leases exclude affiliated-entity fees that exceed market rates.
Vacant-space allocation in a partially-leased building
In a multi-tenant building, CAM is typically allocated pro-rata based on rentable square footage. If you occupy 30% of the building, you pay 30% of CAM. If the building is 80% leased and you're 30% of the leased portion, your "share" of CAM is theoretically 37.5% of the total (30% ÷ 80%).
The two methods produce different numbers. The gross-up method (your share of 100%) is tenant-favorable when the building is partially vacant — the landlord eats the vacancy. The allocation method (your share of leased only) is landlord-favorable — the existing tenants subsidize the vacancy.
What to check: Look at the building's average occupancy during the reconciliation period (it's usually disclosed in the reconciliation backup). If it's below 95% and your CAM share isn't grossed up to 95% occupancy, you're absorbing the landlord's leasing risk. Most modern leases explicitly require gross-up. Older leases often don't — and that absence is exploitable.
Insurance allocated to all tenants regardless of building portion
Property insurance covers the building structure. In a multi-tenant building, it should be allocated by the same pro-rata method as other CAM expenses. But landlords sometimes allocate "additional" insurance categories (umbrella liability, terrorism coverage, environmental) at the same percentage even when those policies disproportionately benefit a portion of the building that you don't occupy.
The classic example: a multi-tenant building with one tenant operating a chemical or food-grade process. The environmental insurance premium is driven entirely by that tenant's risk profile, but it gets allocated to all tenants pro-rata. Industrial tenants without high-risk operations subsidize the high-risk tenant's insurance.
What to check: Pull the insurance schedule. If any policy line is materially larger than market rate for the building type, ask whether it's driven by a specific tenant's operations. If so, your lease may exclude it.
Caps applied to wrong base
Modern industrial leases include controllable op-ex caps — typically 4–5% annually on the "controllable" portion of CAM (excluding taxes, insurance, and utilities). The cap protects tenants from runaway operating cost increases.
The implementation gets sloppy. The cap should be applied to the controllable portion only. Sometimes it gets applied to total CAM (which makes the cap effectively meaningless because uncontrollable categories don't typically grow at controllable rates). Sometimes it gets applied to a base year that wasn't your base year. Sometimes it gets reset every year instead of being a cumulative cap.
What to check: Read your lease's cap language carefully and then check the reconciliation math. The cap should be: (prior year's controllable CAM) × (1 + cap %) = current year's cap. If the math doesn't line up, the landlord owes you the difference.
The economics
On a 75,000 SF industrial building with $1.40/SF CAM, total annual CAM is $105,000. The typical audit recovers 5–15% — $5,250 to $15,750 per year. Over a 7-year lease, that's $37,000 to $110,000. Most leases also allow tenants to recover overcharges going back 12–24 months from the date of audit. A successful audit typically captures 1.5–3 years of historical overcharge plus the prospective correction.
What to do
If you've never had a CAM audit run on your lease, do one. The first audit pays for itself almost every time. After the first audit identifies the recurring patterns, ongoing review takes hours, not days. Even if you decide not to make a claim on past overcharges, the discipline of reading the reconciliation forces the landlord's accounting team to be careful — and that alone reduces future overcharge frequency.