Operating expense audits used to be Big Four work. The mid-sized CPA firms that wanted to add the service line could not get the unit economics to work, because doing the math on a single year of operating expense pass-throughs is a multi-day spreadsheet exercise. I built CAMAudit because the manual workflow priced the service out of every firm under 200 staff, which left tenants paying overcharged operating expenses with nobody auditing them. The economics flip when the analytical work goes from days to under an hour. That is what makes operating expense audits a viable CPA service line in 2026.
What an operating expense audit actually tests
The audit is not about whether the landlord's books are accurate. It is about whether the charges to the tenant are consistent with the lease. The categories you test:
- Management fee. Most leases cap the management fee at 3 to 5 percent of gross expenses. Tests confirm the calculation base and the percentage.
- Gross-up calculation. When a building is below full occupancy, the lease typically requires a gross-up of variable expenses to a stated occupancy floor (usually 95 percent). Tests confirm the gross-up was applied correctly.
- Pro-rata share. The tenant's percentage share of operating expenses. Tests confirm the denominator (rentable square feet) and the numerator (tenant's space) match the lease.
- CAM cap. Year-over-year growth caps on controllable expenses. Tests confirm the cap was honored using the lease formula (cumulative, non-cumulative, or compounding).
- Base year. For base-year leases, the audit tests whether the base year was inflated and whether subsequent years were measured from the correct baseline.
- Excluded categories. Capital improvements, leasing commissions, landlord overhead, original construction costs. Tests confirm none of these are in the operating expense pool.
That is the bulk of the audit. The CFO lease cost recovery playbook covers how the work gets framed for the client; this piece covers what the work actually consists of.
How a CPA runs the audit, mechanically
Step 1. Document collection. Lease, all amendments, the reconciliation statement under audit, prior-year reconciliations if available, estoppel certificates, any tenant correspondence on operating expenses.
Step 2. Document extraction. CAMAudit reads the lease and pulls the cap structure, gross-up clause, pro-rata share, base year if applicable, and the list of expense exclusions. The platform extracts the reconciliation expense data and matches each line item to its lease category.
Step 3. Rule application. The 14 detection rules run against the extracted data. Each rule produces zero or more findings, with calculations and lease citations.
Step 4. Findings review. The senior associate reviews each finding and decides whether it is supportable for a dispute letter. Marginal findings get dropped. Strong findings get included.
Step 5. Deliverable. The findings report, dispute letter draft, and a working memo for the engagement file. The partner reviews and signs.
Total billable time after the first one or two engagements: 4 to 8 hours per audit. That is the math that makes the flat fee profitable. The delivery framework for CPA CAM findings covers how to present the report so the client treats it as a finance work product, not a legal one.
The math the audit produces
A finding looks like this in the working file:
Finding: Management fee overcharge. Lease provision: Section 7.3.2 caps the management fee at 4% of gross operating expenses excluding management fee itself. Reconciliation amount: Management fee billed at 4.5% of gross operating expenses inclusive of management fee. Calculation: Gross expenses ex. management fee = $1,840,000. Permitted management fee at 4% = $73,600. Billed = $86,400. Overcharge = $12,800. Tenant pro-rata share = 8.4%. Recoverable amount to tenant = $1,075.
That is the format. Every finding cites the lease, shows the math, and quantifies the recoverable amount at the tenant level. CAMAudit produces this for every finding. The CPA decides which to include in the demand and which to drop.
What the audit pays
Pricing is the same shape as any other CPA productized service. Three structures show up in practice:
Flat fee. $2,000 to $5,000 per single-year audit on one property. The CPA CAM audit fee schedule covers the full pricing matrix.
Hourly with retainer. Standard rates plus a retainer of $5,000 to $10,000. Best for established advisory clients who already understand the billing model.
Hybrid flat plus contingency. A reduced flat fee plus 20 to 30 percent of recovered overcharges. Check your state CPA board rules on contingency for the relevant client type.
The recurring annual review is where the unit economics get good. Year one is full price; year two costs you a fraction because the lease is already extracted in CAMAudit and the prior-year baseline is built. You can charge 60 to 70 percent of year one and double your effective hourly rate.
Where CAMAudit fits in the audit workflow
CAMAudit handles the analytical compression. The platform extracts the lease, runs the rule-based math deterministically, and produces a findings report and dispute letter draft. The CPA reviews, edits, and signs. The work product looks like a CPA work product because the CPA is the one who delivered it.
If you want to run the service under your firm brand, the white-label CAM audit program for CPAs gives you a co-branded report and dispute letter. The deliverable carries your firm logo. Clients never see CAMAudit. The white-label partner program page covers the branding and engagement template details.
If you would rather refer clients to CAMAudit and split the platform fee, the revenue-sharing program is the alternative. Both routes work; the choice depends on whether you want to own the deliverable under your brand or refer the work and take a smaller margin without engagement risk.
Why operating expense audits belong in a CPA practice
Three reasons. First, the underlying work is finance, not legal. Pass-through testing against a contract is exactly the skill set CPAs already have. Second, the deliverable produces measurable cash recovery, which makes it a renewal lever for advisory engagements. Third, it creates a recurring revenue stream because reconciliations come out annually and the audit can be repeated each year on the same lease.
The CAM audit niche services framework covers how this fits next to other CPA productized service lines (R&D credits, cost segregation, energy credits). Operating expense audit slots in alongside those as a service line that pays well, scales with software, and creates renewable advisory work.
What does not belong in the audit
The CPA does not litigate. The CPA does not draft contracts. The CPA does not file claims. If the dispute escalates beyond a written demand and a negotiation, that is a referral to outside counsel. The advisory services framework for CPA real estate work covers where to hand off and how to structure the referral.
The audit also does not test the landlord's books. The audit tests the lease against the reconciliation. If the landlord refuses to produce supporting backup, that is a right to audit issue and gets escalated to legal counsel.
Run a free scan to test the engagement before pitching
The lowest-friction way to see whether your client base has audit-worthy reconciliations is to run a free scan on one current client. The blurred report shows you the total potential overcharge and the count of findings without unlocking the line items. If three of your five real estate clients have material findings, you have a productized service line. If they all come back clean, you saved yourself a launch.
Frequently Asked Questions
What is an operating expense audit by a CPA?
It is a forensic review of the operating expenses a tenant is being charged under a commercial lease, testing each pass-through against the lease terms, the cap structure, and the tenant's pro-rata share. I built CAMAudit because every CPA who tried to run this by hand told me it was unprofitable, and that left the work undone.
How does a CPA actually run an operating expense audit?
Collect the lease and the reconciliation, separate controllable from non-controllable expenses, test the management fee, gross-up calculation, and pro-rata share, and check for excluded categories. CAMAudit runs the 14 detection rules deterministically and produces a findings report. The CPA reviews and signs.
What does an operating expense audit pay a CPA?
Flat fee per audit ranges from $2,000 to $5,000 for a single-year, single-property review. Multi-year audits scale up. Some firms add a contingency on recovery; some fold it into a higher advisory retainer. The highest-margin variant is the annual recurring review.
Where does CAMAudit fit into an operating expense audit?
CAMAudit is the audit engine. The platform extracts lease provisions, applies the 14 detection rules to the operating expense data, and produces a findings report with calculations and lease citations. The CPA owns the engagement; the software owns the math.
Add operating expense audits to your CPA practice
The fastest way to go live is to white-label the platform under your firm brand. You get the analytical engine, the report templates, and a co-branded findings deliverable that lives under your firm name. The recovery dollars become your renewal lever, and the engagement repeats every year.
See also: Fractional Cfo Real Estate Fees