A CAM audit is a formal review of a landlord's CAM reconciliation statement to verify that charges are accurate, properly calculated, and consistent with the lease. The audit compares the statement line items against the lease's expense definition, pro-rata share formula, gross-up provision, and any caps.

How long does a CAM audit take?

With CAMAudit, a full forensic audit runs in under 15 minutes. Traditional CPA-led audits take 4 to 8 weeks and require scheduling, document collection, and manual review. The speed advantage of CAMAudit comes from automating the extraction and detection steps.

What documents do I need for a CAM audit?

You need your commercial lease (including all addenda and exhibits) and your CAM reconciliation statement from your landlord. The reconciliation is usually sent annually, within 90 to 120 days after the close of the lease year. If you haven't received it yet, request it in writing.

What does a CAM audit actually check?

CAMAudit checks 14 categories: management fee overcharge, pro-rata share error, gross-up violation, CAM cap violation, base year error, controllable expense cap overcharge, estimated payment true-up error, gross lease charges, excluded service charges, insurance overcharge, tax overallocation, utility overcharge, common area misclassification, and landlord overhead pass-through.

Do I need an attorney to dispute CAM charges?

Not necessarily. CAMAudit generates a dispute letter draft grounded in your specific findings and lease language. Many tenants resolve CAM disputes by sending this letter directly to their landlord or property manager. For large disputes or adversarial landlords, involving an attorney is advisable.

Case Study: Base Year Error That Inflated a Restaurant's CAM Costs for Six Years

A fast-casual restaurant franchise operator in Illinois signed a triple-net lease in 2019 on a 2,800-square-foot space in a mixed-use retail center. Six years later, a CAMAudit scan revealed the lease's base year had never been calculated correctly — and the error had compounded across every single reconciliation since.

The Scenario

The tenant operated under a base year stop structure. Their lease specified 2019 as the base year, meaning they would only owe CAM charges above the 2019 expense level. On paper, this is a standard, reasonable arrangement.

The problem: the building was only 60% occupied in 2019. Expenses that year were unusually low — not because the landlord ran an efficient property, but because there simply weren't enough tenants to generate normal operating costs.

The landlord reported base year operating expenses of $18.50 per square foot. No gross-up was applied. No footnote explained the occupancy level. The number looked unremarkable on paper.

Annual CAM bill: approximately $51,800 at the current run rate.

What Triggered the Audit

The tenant received their 2025 CAM reconciliation statement and noticed the annual charge had climbed steadily every year — more than they expected for a stable retail center. They uploaded their lease and reconciliation to CAMAudit.

What CAMAudit Found

CAMAudit's Rule 7 (Base Year Error) flagged the base year stop immediately. The detection engine identified that the lease contained a gross-up provision — though a vague one — and that the stated base year expenses of $18.50 PSF were significantly below market for comparable occupied retail centers in the region.

The engine flagged: Base year expenses appear understated. Verify building occupancy in the base year. If occupancy was below 95%, base year expenses should be grossed up to 95% occupancy per the lease's gross-up provision.

"The gross-up clause in this lease was ambiguous — it referenced 'variable operating expenses' without defining the term precisely. That ambiguity is exactly what landlords rely on. But the intent of a base year stop is to protect a tenant from absorbing occupancy risk that isn't theirs. When the building was 60% full in the base year, the tenant was locked into a starting point that was structurally depressed." — Angel Campa, Founder of CAMAudit

The Math

The tenant pulled the 2019 occupancy data from the county assessor's public property records. The building was 60% occupied that year.

The gross-up calculation is straightforward: take the base year variable expenses and scale them to what they would have been at 95% occupancy.

Stated base year expenses: $18.50 PSF
Grossed-up base year (at 95% occupancy): $28.20 PSF
Annual overcharge per square foot: $28.20 − $18.50 = $9.70 PSF
Annual overcharge for 2,800 sq ft: $9.70 × 2,800 = $27,160/year
Lease term with the error: 2020–2025 (6 years)
Total overcharge: $27,160 × 6 = $162,960

Illinois has a 10-year statute of limitations on contract disputes, meaning the entire six-year overcharge was potentially recoverable.

40% of CAM reconciliations contain material errors (Tango Analytics/PredictAP, 2023)

The Resolution

The tenant drafted a dispute letter using CAMAudit's output as the foundation. The letter cited:

The specific 2019 occupancy rate (60%) sourced from public property records
The implied gross-up requirement under the lease's variable expense provision
The year-by-year overcharge calculation across all six reconciliation periods

The landlord's property management company initially pushed back, arguing the gross-up clause only applied to janitorial and utilities — not the full expense pool. The tenant's response cited the lease's definition of "variable operating expenses" and requested a line-item breakdown of what the landlord classified as fixed versus variable in 2019.

The parties reached a settlement for a four-year lookback: $27,160 × 4 = $108,640 applied as a credit against future rent.

The tenant left $54,320 on the table (the first two years), but avoided litigation and recovered the majority of the overcharge within 90 days of sending the dispute letter.

Key Takeaway

A base year set during a low-occupancy period is one of the most expensive and least obvious errors in commercial leasing. The landlord isn't necessarily acting in bad faith — 2019 was a real year with real numbers. But those numbers don't reflect a normally operating property, and using them as the permanent benchmark locks tenants into absorbing all future occupancy normalization as expense growth.

Watch for this if:

Your base year is 2019, 2020, or 2021 (all abnormal occupancy years)
Your lease has a gross-up provision that doesn't clearly define "variable" versus "fixed" expenses
Your CAM charges have grown faster than the CPI or comparable properties in your market

If your lease has a base year stop structure, verify what occupancy rate was in effect during that year before accepting the starting benchmark. Your audit rights clause gives you the standing to request it.

For a deeper look at how base year errors compound over time, see how to calculate a multi-year CAM overcharge.

FAQ

What is a base year stop in a commercial lease?

A base year stop is a lease structure where the tenant pays a fixed base amount for CAM expenses — equal to the actual operating expenses in a specified year — and only owes additional charges when expenses exceed that baseline. The base year amount is supposed to reflect normal property operations. When it doesn't (because the building was partially vacant), every reconciliation period after that is distorted.

Can a landlord set a base year without grossing up for vacancy?

Some landlords do, and some leases permit it — but leases that contain gross-up provisions are meant to prevent exactly this outcome. If your lease says variable operating expenses shall be grossed up to 95% occupancy, that provision applies to the base year calculation as well as annual reconciliations. A base year set at 60% occupancy without gross-up defeats the purpose of the stop entirely.

How far back can I recover CAM overcharges in Illinois?

Illinois has a 10-year statute of limitations on written contract disputes, which typically includes commercial lease CAM reconciliations. However, your lease may contain a shorter audit rights window — commonly 12–24 months from the date the reconciliation statement was delivered. The shorter of the two windows controls what you can formally dispute. Work with a commercial real estate attorney to confirm the applicable period for your specific lease before sending a demand.

Case Study: Base Year Error That Inflated a Restaurant's CAM Costs for Six Years