CAM Reconciliation in Commercial Leases: Shares, Gross-Ups and the Year-End True-Up

Wiss & Company, an accounting and advisory firm, gives the core formula: the tenant’s leased square footage divided by the property’s total leasable square footage, multiplied by total annual CAM expenses. [Wiss & Company, LLP, read 2026-09-26]

Its worked example: a retail center with $250,000 in annual CAM expenses and a tenant occupying 15% of the leasable space gives an annual obligation of $37,500, or $3,125 a month. [Wiss & Company, LLP, read 2026-09-26]

Accruent, a lease-administration software vendor, gives a retail version: a 4,000-square-foot store in a center with 100,000 square feet of gross leasable area carries a 4 percent share. [Accruent, read 2026-09-26]

Wiss says CAM runs on an estimate-and-true-up cycle under triple-net and double-net leases. Under a gross lease, operating costs including CAM are bundled into fixed rent, with no separate CAM line. [Wiss & Company, LLP, read 2026-09-26]

Wiss says the definition of the denominator, total leasable square footage, meaningfully affects the amount billed. [Wiss & Company, LLP, read 2026-09-26]

Tango Analytics, a lease-administration software vendor, gives examples of how landlords measure shares: counting only usable square footage or including the walls, and distinguishing leased, leasable, occupied or existing space. [Tango Analytics, read 2026-09-26]

Accruent says anchor tenants are frequently excluded from the area used for common-area costs, which raises every other store’s share. [Accruent, read 2026-09-26]

Denominators can also differ by cost category, it says, and leasable area moves when a center adds or reconfigures space mid-year. [Accruent, read 2026-09-26]

Area itself is measured under published standards. BOMA International, the ANSI secretariat for a suite of area measurement standards, says they are considered the de facto building measurement standards in many real estate markets. [BOMA International, read 2026-09-26]

BOMA publishes separate standards for office, industrial, retail, mixed-use, and multi-family and hospitality properties. Its office standard exists mainly to calculate rentable area; BOMA says it also yields figures useful for allocating building expenses across different cost centers. [BOMA International, read 2026-09-26]

The BOMA page describes how area is measured, not how a lease divides CAM among tenants. [BOMA International, read 2026-09-26]

Tango describes a gross-up clause as inflating CAM expenses to what they would be at full occupancy, then billing each tenant its pro-rata share of that inflated figure. [Tango Analytics, read 2026-09-26]

Its example: a five-space building with four tenants is 80% occupied and has $800 of CAM expenses. Grossed up to $1,000, each tenant’s 20% share comes to $200 instead of $160. [Tango Analytics, read 2026-09-26]

Tango says the four tenants thereby make up for the missing fifth, covering the $800 themselves rather than leaving the landlord on the hook. [Tango Analytics, read 2026-09-26]

Holland & Hart (2007) says a gross-up benefits the landlord because it shifts some of the responsibility for vacancies to the tenant. [Holland & Hart LLP, read 2026-09-26] Thompson Coburn (2017) makes the same point. [Thompson Coburn LLP, read 2026-09-26]

Wiss describes gross-ups differently: as provisions that adjust the denominator to reflect a hypothetically fully occupied property. It says they are designed to keep tenants from shouldering a disproportionate share of costs because of vacancies. [Wiss & Company, LLP, read 2026-09-26]

The other sources that explain gross-ups describe grossing up expenses, not the denominator. Wiss adds that whether a gross-up applies depends entirely on what the lease says. [Wiss & Company, LLP, read 2026-09-26]

Holland & Hart (2007) says only costs that vary with occupancy should be grossed up, such as electricity, trash removal, management fees and janitorial services. Taxes, insurance and building security should not be. [Holland & Hart LLP, read 2026-09-26]

Thompson Coburn (2017) draws the same line: janitorial, trash and utilities vary with occupancy, while insurance premiums and real estate taxes do not. [Thompson Coburn LLP, read 2026-09-26]

The occupancy level is negotiated. Holland & Hart (2007) puts it at 95% or 100%, with compromises such as 75% or 80%. [Holland & Hart LLP, read 2026-09-26] Thompson Coburn (2017) mentions 80-85% as a compromise. [Thompson Coburn LLP, read 2026-09-26]

Newer sources are similar. Donna Wheeler, a Cushman & Wakefield associate director, said gross-ups are often based on 95% or 100% occupancy, according to a June 2025 Buildings preview of her BOMA International conference session. [Buildings, read 2026-09-26]

Accruent, writing in 2026, says 95 percent is common. [Accruent, read 2026-09-26]

Calculation methods differ too. Wheeler described a simple method and a second one that assumes part of a utility bill would be incurred even with no tenants. [Buildings, read 2026-09-26]

Under that second method, the fixed portion is not grossed up. She put the fixed share of electricity at 30 to 35% across the market. [Buildings, read 2026-09-26]

In a base-year lease, Thompson Coburn (2017) explains, the tenant pays only its share of operating expenses above the base year. [Thompson Coburn LLP, read 2026-09-26]

Without a gross-up, a partly empty base year keeps that starting level low, so the tenant’s share jumps as the building fills. [Thompson Coburn LLP, read 2026-09-26]

Grossing up the base year raises the starting level. Thompson Coburn says this protects the tenant from a big spike in its share; [Thompson Coburn LLP, read 2026-09-26] Holland & Hart (2007) makes the same point. [Holland & Hart LLP, read 2026-09-26]

Holland & Hart also advises tenants to make sure they never owe grossed-up amounts beyond what the landlord actually pays, and to be able to review the landlord’s calculation. [Holland & Hart LLP, read 2026-09-26]

Landlords often estimate shared costs from historical data and bill them monthly, Tango says. Reconciliation checks whether those estimated payments were correct. [Tango Analytics, read 2026-09-26]

Wiss says that if actual costs exceed the estimates, the tenant owes a true-up payment. If estimates exceed actual costs, the landlord issues a credit or refund. [Wiss & Company, LLP, read 2026-09-26]

Tango, writing for tenants, says reconciliation sometimes produces a reimbursement, but more often the tenant has to make up the difference. [Tango Analytics, read 2026-09-26]

A 2020 post from Cushman & Wakefield’s Dallas office, written from the tenant’s side, says a credit does not prove the billing was accurate; it may only reflect high estimated payments. [Cushman & Wakefield, read 2026-09-26]

The same post says most leases require the tenant to pay a balance due within 30 days. [Cushman & Wakefield, read 2026-09-26]

Wiss says the statement should come with detailed expense records, vendor invoices, occupancy figures and a written description of the allocation method. [Wiss & Company, LLP, read 2026-09-26]

Accruent says the lease sets the deadline for the reconciliation statement, along with the review period that follows. [Accruent, read 2026-09-26]

Tango says reconciliations may be due within 30 to 90 days after December 31, depending on the lease. [Tango Analytics, read 2026-09-26]

Harvest LLP, a real estate law firm writing in 2025, advises landlords to deliver the statement as soon as possible, typically within 90 to 120 days of the lease year’s end. [Harvest LLP, read 2026-09-26]

Wiss puts the typical window at 90 to 180 days after the calendar year closes, as the lease specifies. [Wiss & Company, LLP, read 2026-09-26]

Tango adds that reconciliation season for many major landlords starts right after the new year and runs through the spring. [Tango Analytics, read 2026-09-26]

Wiss says many leases cap annual CAM increases, commonly at 3% to 5%. In some leases the cap covers only controllable expenses, and utilities, insurance and real estate taxes may be carved out. [Wiss & Company, LLP, read 2026-09-26]

Tango separates controllable expenses, which often carry a cap, from non-controllable ones such as utilities, snow removal and taxes, which usually do not. [Tango Analytics, read 2026-09-26]

Accruent advises checking whether a cap is cumulative. One error it lists is a compounding cap applied as though it were non-cumulative. [Accruent, read 2026-09-26]

Wiss says capital expenditures, depreciation, financing costs and leasing commissions are typically excluded. Management fees are typically included when the lease explicitly states they are recoverable. [Wiss & Company, LLP, read 2026-09-26]

Wiss calls the line between capital work and maintenance the most frequently contested category, using parking-lot resurfacing as its example. [Wiss & Company, LLP, read 2026-09-26] Accruent says capital costs, where the lease makes them recoverable, are typically amortized over the equipment’s useful life. [Accruent, read 2026-09-26]

Tango says a tenant who moves in or out mid-year should not be billed for a full year, and a tenant whose space changes may be owed two reconciliations for one year. [Tango Analytics, read 2026-09-26]

The 2020 Cushman & Wakefield Dallas post says most leases let tenants review the annual reconciliation within 30 to 180 days of receiving the landlord’s statement. [Cushman & Wakefield, read 2026-09-26]

Accruent says many leases allow only 30 to 90 days to object, and that once the window closes the statement generally becomes final. [Accruent, read 2026-09-26]

The Cushman post also says that even where a lease is silent on audit rights, most states have laws that would allow a tenant to review the expenses. It does not name those laws. [Cushman & Wakefield, read 2026-09-26]

It adds that paying a balance due does not waive the audit rights provided in the lease. [Cushman & Wakefield, read 2026-09-26] The post cites no clause or law for this, so the lease’s own wording is the place to check.

Harvest (2025) cautions that a lease may limit audits to the previous year, and that statutes of limitations may limit recovery of older overbilling. [Harvest LLP, read 2026-09-26]

Accruent says many leases shift the audit’s cost to the landlord once an overcharge passes a stated threshold, sometimes as low as 3 percent of operating expenses. [Accruent, read 2026-09-26]

Tango’s explanation is that every lease is unique: similar wording applies differently by location, co-tenants and changing circumstances, so a clause is easy to miss. [Tango Analytics, read 2026-09-26]

Accruent’s list of frequent findings includes wrong shares or denominators, excluded costs, capital work billed as operating expense, management fees above the lease’s percentage, misapplied caps and duplicate charges. [Accruent, read 2026-09-26]

Wiss says tenant objections and disputes almost always trace back to imprecise lease language or documentation gaps, not to expense levels. [Wiss & Company, LLP, read 2026-09-26]

Wiss recommends tracking actual against budgeted CAM costs monthly. [Wiss & Company, LLP, read 2026-09-26] Tango recommends recording the date each statement arrives and comparing its total with the prior year’s. [Tango Analytics, read 2026-09-26]

Wheeler, in the Buildings preview, describes keeping a per-lease summary of gross-up percentages, caps and what is in each tenant’s CAM pool. [Buildings, read 2026-09-26]

Tango, which sells such tools, recommends software that checks CAM against each lease’s language, caps, exclusions and share variations. [Tango Analytics, read 2026-09-26]