CAM overcharges affect 40% or more of commercial leases. Here's a breakdown of the most common error types, where they appear, and how much tenants typically recover.
TL;DR: Roughly 40% of commercial CAM reconciliations contain material billing errors. Management fee overcharges and pro-rata share errors are the most common. Base year errors are often the most expensive because they compound annually. Most errors are not intentional fraud: they are software misconfiguration, lease provisions not programmed correctly, or allocation methods that drift from what the lease requires.
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Find My OverchargesSee a sample report first“I built CAMAudit after seeing how often reconciliation errors went unchallenged. The contingency audit industry exists because recoveries are reliable. That tells you something about how systematic these errors are.”
The CAM audit industry exists because overcharges are common enough to support a business model built on finding them. Contingency auditors, who charge 25-33% of recovered amounts, would not have a viable practice if errors were rare. The fact that the industry has sustained itself for decades is a signal about how frequently reconciliation errors occur.
This report covers the most common overcharge types, how often they appear, what they typically cost tenants, and how errors actually happen in practice.
The 40% figure from Tango Analytics represents material errors: charges that are demonstrably incorrect under the tenant's lease terms and that result in an overcharge the tenant did not owe. A separate estimate from industry practitioners puts the number closer to 70% for all errors including minor calculation differences, though the materiality threshold affects how you read that number.
What is not disputed: the professional audit industry is built on finding these errors. Traditional firms charge $2,000-$5,000 upfront plus 25-33% contingency on recovered amounts. If those firms were frequently completing audits and finding nothing, they would not stay in business. The economics of the contingency model validate the frequency of the problem.
The audit season runs February through May each year. Most landlords issue reconciliation statements for the prior year in January or February. Tenants typically have 30-180 days from receipt to dispute, depending on lease language. The combination of a short dispute window and the complexity of the calculations is one reason so many overcharges go unchallenged.
Frequency: 15-25% of audited NNN leases
Management fee overcharges are one of the most consistently flagged error types in commercial CAM audits. Most commercial leases cap management fees as a percentage of operating expenses or gross revenues. Common caps range from 3% to 5%.
The overcharge occurs when the property management company applies a fee rate above the contractual cap, calculates the fee on a broader base than the lease permits, or includes management fee amounts that belong to other properties in the building's expense pool.
A typical example: A lease caps management fees at 4% of operating expenses. The property management company charges a flat 5% rate across all tenants because that is what their software is configured to bill. On a $500,000 operating expense pool, the difference is $5,000 per year, or $15,000 over a standard 3-year lookback.
Management fee errors are among the easier overcharges to document because the lease provision is typically explicit ("management fee shall not exceed 4% of gross operating expenses") and the calculation is straightforward.
Frequency: Among the most common findings; exact rate varies by property type
Pro-rata share errors occur when the denominator used to calculate a tenant's share of CAM expenses is incorrect under the lease. The denominator is typically the total rentable square footage of the building or the project, but leases vary significantly in how they define it.
Some leases define the denominator as total gross leasable area (GLA). Others use a different measurement standard. Some exclude anchor tenant space from the denominator. Some include or exclude parking structures. When the property management company applies the wrong denominator, every year's allocation is wrong.
The OAG audit case is one of the most well-documented examples in the public record. In that audit, a single pro-rata share error resulted in $55,421 in excess charges over six years. The error was not in the annual rate: it was in the base denominator, which compounded the overcharge across the entire lease term.
Pro-rata share errors are particularly significant because they affect every category of CAM expense simultaneously. If the denominator is 5% too small, every line item in your CAM bill is 5% too high. The compounding effect makes these errors expensive even when the percentage error is relatively small.
Frequency: 25-35% of audited leases with gross-up provisions
Gross-up provisions allow landlords to normalize variable operating expenses (typically utilities and janitorial) to the level they would be at full occupancy. The theory is that tenants should pay their share of what costs would be at full occupancy, not their share of the actual lower cost at, say, 75% occupancy. Without gross-up, tenants in partially occupied buildings effectively subsidize the landlord's vacant space costs.
The provision is legitimate. The errors happen in the application.
Common gross-up violations:
Applying gross-up to non-variable expenses. Fixed costs like property taxes, insurance premiums, and management fees do not change based on occupancy. Grossing them up to 100% occupancy creates fictional expenses that tenants should not pay.
Using the wrong occupancy threshold. Most leases specify a gross-up threshold (commonly 95%). If the building is at 92% occupied, gross-up applies. If it is at 97% occupied, it should not. Property management software misconfigured to always apply gross-up will overcharge tenants even in fully-occupied buildings.
Incorrect calculation of the variable component. The gross-up formula normalizes only the variable portion of eligible expenses, not the total expense. Grossing up the full line item instead of the variable portion inflates the calculation.
Frequency: 15-25% of leases with CAM caps
Many commercial leases include a cap on annual CAM increases. Common structures: a fixed percentage cap per year (4-5% annually), a CPI-linked cap, or a controllable expense cap that applies to specific categories.
CAM cap violations occur when the landlord's charges exceed the contractual ceiling in a given year. These errors often happen because the property management software tracks actual expenses but does not automatically apply the lease-specific cap before billing the tenant.
The compounding structure of caps creates additional complexity. A cumulative cap (where unused cap capacity carries forward) calculates differently from a simple annual cap. If the property manager applies a simple cap formula to a cumulative cap lease, or vice versa, the error compounds across multiple years.
Frequency: 15-25% of base-year leases; typical annual impact $1-2 per square foot
Base year leases calculate tenant CAM charges as the amount by which current-year expenses exceed the base year expenses. If the base year is set too low, the tenant overpays in every subsequent year. If non-recurring or one-time expenses were excluded from the base year that should have been included, the ongoing expense comparisons are distorted.
Base year errors are the most expensive error type for long-term tenants because they compound. A $50,000 base year understatement in year one translates to $50,000 per year in additional charges for every subsequent year of the lease. On a 10-year lease, that is a $500,000 aggregate overcharge from a single error in the base year calculation.
Base year errors are also among the harder overcharges to recover retroactively because many leases have lookback windows that limit dispute rights to 2-3 years. Tenants who catch a base year error early can dispute years two and three. Tenants who catch it in year eight have already absorbed most of the compounded cost.
Frequency: Varies significantly; common in properties with active capital programs
Most commercial leases explicitly exclude certain categories of expenses from the CAM pool. Capital expenditures are the most common exclusion. Leases typically prohibit landlords from passing through the cost of replacing major building systems (HVAC, elevators, roofs) as an operating expense, though amortized costs of capital improvements that benefit tenants may be permitted under specific conditions.
Excluded expenses also commonly include: landlord's corporate overhead, executive compensation above reasonable property management costs, costs related to vacant space preparation, legal fees for landlord-tenant disputes, and expenses attributable to other properties.
Excluded expense errors occur when property management software allocates these costs to the building's operating expense pool without filtering them against the lease exclusions. This often happens during transitions: a property management company takes over a building, inherits the prior manager's expense categorizations, and does not review them against each tenant's individual lease.
The investigation required to find these errors is more intensive than a management fee or pro-rata calculation check. It requires reviewing the underlying ledger at the line-item level and comparing each expense category to the lease's exclusion list.
Most CAM billing errors are not intentional. The commercial real estate industry's management of CAM calculations is largely software-dependent, and that creates three systematic sources of error.
Lease provisions not programmed correctly. When a new tenant moves in or a lease renews, someone at the property management company needs to enter the tenant's specific lease provisions into the property management software. Management fee caps, CAM caps, gross-up thresholds, and pro-rata share definitions all need to be configured per tenant. When provisions are entered incorrectly or incompletely, the software bills incorrectly from day one.
Software configuration that drifts from lease requirements. Even when correctly configured initially, software configurations change. System upgrades, staff turnover, and portfolio acquisitions all create opportunities for configurations to be reset or overwritten.
Allocation methods applied across a portfolio without lease-specific review. Property management companies often manage dozens or hundreds of properties. They apply standard allocation methods across the portfolio and review individual lease deviations manually. When a specific tenant's lease requires a non-standard calculation, it may fall through the cracks of a portfolio-level review.
This is why errors are systematic rather than random. A misconfigured denominator affects every year's calculation until someone catches it.
Recovery depends on three factors: the type of error, the size of the claim, and how much lease term remains.
Type of error. Management fee overcharges and pro-rata share errors are the most reliably recoverable because the calculation is clean and the lease provision is typically explicit. Gross-up violations and excluded expense pass-throughs are harder to negotiate because they involve more interpretation.
Size of the claim. Landlords are more motivated to resolve large claims formally. A $3,000 dispute may be settled informally with a credit against the next month's CAM estimate. A $40,000 dispute involving multiple years and multiple error types typically requires a formal dispute letter draft, supporting documentation, and a negotiation process that runs 60-120 days.
Remaining lease term. Tenants with 3+ years remaining on their lease have more leverage because the landlord values their continued tenancy. Tenants in the last year of their lease are in a different negotiating position and may need to pursue recovery more aggressively or accept a partial settlement rather than extend the dispute past lease expiration.
The general pattern in the industry: when landlords receive a formal dispute with specific documentation, 60-80% result in some credit or correction. Generic complaints without calculations or lease citations rarely produce results.
I built CAMAudit because the math here is deterministic. Management fee caps are either honored or they are not. Pro-rata denominators are either correct under the lease or they are not. The calculations are not subjective. What was missing was a tool that could run these checks systematically, at a price that makes annual review economically sensible for tenants who are not running multi-million-dollar portfolios.
Traditional audit firms charge $2,000-$5,000 to start, plus a third of what they recover. That model makes sense for large properties with large claims. It does not make sense for a 3,000 square foot office tenant with a potential $4,000 overcharge. At $199 per audit, CAMAudit makes annual verification accessible for tenants at any scale.
The data is consistent: overcharges are common, they are systematic, and they are recoverable when documented properly.
For the full methodology behind what CAMAudit checks, see CAM Audit Methodology. For the step-by-step process of running a lease review, see the Commercial Lease Audit Guide.
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