The invoice lands in the inbox. It says $18,000 due for the annual CAM reconciliation. The client's monthly estimates totaled $14,400 over the year, so there is a $3,600 balance. Before anyone types a journal entry, there is a question that needs answering: does this number have any support behind it?. For more context, see how to request CAM support documents.
Most accounting teams code and pay CAM true-ups without asking. The property manager sends a reconciliation statement, someone checks that the math adds up on its face, and the bill goes through. That works fine until it does not. When our tool has flagged overcharges in CAM reconciliations, the most common root cause is not a landlord acting in bad faith. It is a documentation gap that nobody thought to close before the check went out.
This article covers exactly what to request, how to ask for it, and what to do when the property manager does not respond.
Why Backup Matters Before Coding
A CAM reconciliation statement is a summary. It shows total expenses, total recoverable costs, the client's pro-rata share percentage, and the resulting balance. What it does not show is whether any of those numbers are correct.
A $7,800 tax pass-through looks reasonable on a reconciliation statement. But if you pull the actual tax bill and apply the correct pro-rata share, the number might be $6,400. The difference does not show up anywhere in the summary. You need the backup to find it.
The same logic applies to management fees. A 4% management fee on $180,000 in CAM expenses is $7,200. But if the lease caps the management fee base at gross revenues rather than CAM expenses, and if the landlord applied it to a larger base that includes items outside the lease's definition, the fee could be $9,400. Again: that does not show up in a summary statement. You need to see how the base was calculated.
Coding without backup is not just a financial risk. It is a liability question. If a client later disputes the charge and the payment went through without documentation, your firm may have limited options.
The Six Documents to Request
1. Line-Item Expense Detail
This is the full ledger of every expense included in the CAM pool for the year. It should include the expense category, the amount, and whether it is classified as recoverable. This is the document that lets you spot excluded expenses billed as CAM, capital improvements coded as operating expenses, or duplicate line items.
For a law firm tenant in a 40,000 square foot building, the CAM pool might include 80 to 120 line items. You need all of them, not just the category totals.
2. Pro-Rata Share Calculation
This should show three numbers: the tenant's rentable square footage, the total leasable area used as the denominator, and the resulting percentage. Check the square footage against the lease. Check the denominator against the building size stated in the lease. Both are frequent sources of error.
Some leases exclude certain tenant spaces from the denominator. Some use "leasable area" rather than "occupied area," which matters when gross-up provisions apply. If the denominator is wrong, the entire allocation is wrong.
3. Management Fee Base and Rate
Request the calculation showing the management fee base (what dollar amount the percentage was applied to), the rate, and the result. Compare the base definition against the lease language. Leases define the management fee base in different ways. Some say "gross revenues," some say "CAM expenses," some include taxes and insurance and some do not.
A $1,200 per month management fee that sounds reasonable at first glance might be the result of a 5% rate applied to a $24,000 monthly base that includes excluded items. The math is correct; the base is the problem.
4. Utility Allocation Methodology
If utilities are included in CAM (common in multi-tenant office buildings and retail centers), request the methodology used to allocate them between tenants. Some buildings sub-meter; some estimate based on square footage; some use occupancy hours. The methodology should match what the lease authorizes.
For a dental practice client in a medical office building, utilities can be a significant part of the CAM bill. If the space uses specialized HVAC or power for equipment, the allocation method matters a great deal.
5. Capital Expenditure Detail
If the reconciliation includes any amortized capital improvements, request the original invoice and the amortization schedule. Many leases exclude capital expenditures from CAM entirely, or limit recovery to specific categories like life-safety systems. Others allow recovery but cap the amortization period.
A landlord who amortizes a roof replacement over 10 years and passes the annual amount through as a CAM expense may be in violation of the lease if the lease excludes structural capital improvements.
6. Insurance Certificate or Premium Summary
If insurance is passed through separately or as part of CAM, request a copy of the premium summary. The charge should reflect the actual premium for the policy period, prorated to the tenant's share. Overcharges in this category often come from landlords billing an estimated premium when the actual premium was lower.
How to Request the Documents
Keep the request professional and specific. Here is the language that works:
"We are reviewing the 2025 CAM reconciliation before processing payment. To complete our review, we need the following supporting documentation: (1) line-item expense detail for all costs included in the CAM pool, (2) the pro-rata share calculation with square footage support, (3) management fee base and rate detail, (4) utility allocation methodology, and (5) any capital expenditure or insurance detail included in the reconciliation. Please send these documents within 10 business days. We will complete our review promptly upon receipt."
Send by email. Keep a copy. If the property manager has a tenant portal, upload the request there as well so it is timestamped.
Do not frame this as adversarial. Most property managers respond without friction when the request is matter-of-fact. The framing matters.
What to Do When the Property Manager Does Not Respond
If 10 business days pass without a response, send one follow-up. Keep the tone neutral and reference the original request date.
If there is still no response after the follow-up, do not simply code and pay. Code the amount to a suspense account or a prepaid CAM account, document the request in the client file, and flag the item for client review. The client needs to know that backup was requested and not provided.
In most cases, a brief note from the client to the property manager resolves the standoff faster than any accounting follow-up can. Property managers tend to be more responsive to tenants than to their accountants.
If the client's lease contains audit rights, and most commercial leases do, the right to request supporting documentation is not a courtesy. It is a contractual entitlement. A property manager who refuses to provide backup documentation after a written request is in a legally interesting position, and your client's attorney should know about it.
What Backup Enables
Getting documentation before coding does two things. First, it creates a defensible paper trail. If the charge is paid and later questioned, the file shows what was reviewed and what was approved.
Second, it opens the door to a real review. I built CAMAudit because accounting teams kept finding themselves in a situation where they had the invoice but not the information needed to evaluate it. With line-item detail, a pro-rata share calculation, and a management fee breakdown in hand, it is possible to run those numbers through a structured review and flag the issues that summary statements hide.
When our tool flagged a $3,400 overcharge in a retailer's annual reconciliation, the root issue was a management fee base that included tenant reimbursements alongside CAM expenses. The reconciliation statement showed a single management fee line. The backup showed how it was calculated. Without the backup, there was nothing to flag.
The request takes five minutes to write. The review it enables can recover thousands.
"The reconciliation statement tells you what the landlord charged. The backup documents tell you whether they were authorized to charge it. You need both before you code anything." — Angel Campa, Founder of CAMAudit
Building the Request into Your Workflow
The most efficient approach is to treat backup documentation as a precondition for processing any annual CAM true-up above a threshold amount. For most practices, $2,000 is a reasonable floor. Below that, the review cost may exceed the risk. Above it, the documentation request is worth the five minutes it takes.
For monthly CAM estimates, no backup request is needed. Estimates are coded and paid as routine occupancy expenses. The review trigger is the reconciliation, not the monthly invoice.
Build the backup request into your AP workflow as a step that fires automatically when an annual CAM reconciliation arrives. The request goes out the same day the invoice lands. By the time the payment is due, the documentation should be in hand. If it is not, the payment gets held pending client direction.
That is the workflow. It is not complicated. It just requires treating CAM reconciliations differently from routine invoices, which they are.