How Do I Avoid Paying for Vacant-Space Costs in CAM?

Why vacancy costs land on you without a gross-up

Operating expenses split into two buckets, and understanding the split is the whole game. Fixed costs — property taxes, building insurance, the management base fee — don't move much with how full the building is. Variable costs — janitorial, common-area utilities, trash removal, landscaping, supplies, and consumables — scale directly with occupancy. Empty suites don't need nightly cleaning, don't run the HVAC hard, and don't fill dumpsters. The trap is not that vacancy raises the total bill; it's how the landlord *allocates* the variable portion across the tenants who are actually paying.

Picture a 100,000-square-foot building running at 60% occupancy. When the building is full, variable janitorial runs about $200,000 a year, or roughly $2.00 per rentable square foot. At 60% occupancy the landlord's actual janitorial spend drops to maybe $120,000, because 40,000 square feet sits dark and doesn't get cleaned. So far, fair. The abuse begins when the landlord divides that $120,000 across only the 60,000 occupied square feet — producing an effective rate of $2.00 per square foot billed against you, even though the building is running lean. Then the building fills back to 95%, janitorial climbs to about $190,000 spread over 95,000 square feet, and your rate is *still* around $2.00. Notice what happened: your per-square-foot cost never dropped during the vacancy, even though the landlord's real efficiency improved. You quietly absorbed the inefficiency of an empty building.

On a 5,000-square-foot suite, a mishandled vacancy pass-through of this kind commonly costs a tenant $8,000 to $15,000 a year during a soft market — real money that compounds over a five- or ten-year term. The single clause that neutralizes this is the gross-up, which flips the allocation math so vacancy can't inflate your denominator or your rate. Without it, you are effectively co-signing the landlord's leasing risk while getting none of the upside when the building fills.

How a gross-up clause actually protects you

A gross-up provision reads, in plain terms: *variable operating expenses shall be adjusted as if the building were 95% (or 100%) occupied throughout the year.* The landlord calculates what janitorial, utilities, and trash *would* cost at near-full occupancy, then bills each tenant only their fixed pro-rata share of that grossed-up number. Counterintuitively, tenants often fear the gross-up because it sounds like the landlord is inflating costs — but written correctly, it is tenant insurance against vacancy swings, not a weapon against you.

Here is why it works in your favor:

• It locks your per-square-foot rate. Because costs are always computed against a stable 95%-occupied baseline, your CAM per square foot stays roughly constant whether the building is 60% or 95% full. No vacancy spike lands on your statement.
• It kills the shrinking-denominator abuse. The landlord cannot divide real costs across only the paying tenants, because the formula assumes a near-full building regardless of who has actually signed a lease.
• It keeps the landlord honest when the building fills. When occupancy rises, you don't suddenly get charged for the additional tenants' incremental usage beyond your fixed share — you were already being billed as if they were there.

The real negotiation is over the gross-up percentage, and this is where tenants lose money without realizing it. Push for 95%, not 100%. At 100%, the landlord grosses up variable costs to a fully occupied scenario that many multi-tenant buildings never actually reach, slightly overstating expenses every year. At 95%, you get the vacancy protection without subsidizing a phantom full building. Equally important: insist the gross-up applies only to variable expenses. Fixed costs like property taxes and insurance don't change with occupancy, so grossing them up is pure overcharge — a common landlord "error" worth catching in the lease language before you ever sign.

The exclusions that keep vacant-space costs out entirely

The gross-up governs how *legitimate* variable operating costs get allocated. Separately, landlords try to recover the direct costs of their own vacancy through CAM — and those costs should be flatly excluded from the operating-expense definition, not merely grossed-up around. If a cost exists *because* a suite is empty, it is the landlord's cost of doing business, and no amount of clever allocation math should route it to you. Get the following struck from the lease's operating-expense definition:

• Leasing commissions and broker fees paid to fill vacant space. This is the landlord's acquisition cost for revenue you'll never see.
• Tenant-improvement allowances and buildout costs for other tenants. You should never pay to renovate a neighbor's or competitor's suite so the landlord can close a new deal.
• Marketing, advertising, signage, and model-suite costs used to lease empty space. Pure landlord expense.
• Capital expenditures — roof replacement, full HVAC system replacement, structural work — unless narrowly amortized over the improvement's useful life, and even then only the portion legally required or that demonstrably reduces operating costs. Cap the annual amortized amount so a single big-ticket project can't blow up one year's bill.
• Costs reimbursed by insurance, warranties, or other tenants, to prevent double recovery on the same dollar.
• The landlord's corporate overhead, ground-lease rent, financing costs, and legal fees for disputes or refinancing.

The structural fix is to demand the operating-expense definition be a closed, enumerated list of permitted costs, not an open-ended "all costs of operating, maintaining, and managing the building." Open-ended language is where vacancy costs, capital projects, and the landlord's overhead quietly migrate onto your statement. A tenant-rep rule of thumb: read every line of the CAM definition assuming the landlord will interpret each ambiguity in their favor, because on the reconciliation statement, they will.

Fixing the denominator: total rentable, not occupied

The gross-up protects the numerator — the total pool of costs being allocated. The denominator, meaning the square footage your share gets divided by, needs its own explicit protection, and this is where a surprising number of leases quietly shift vacancy risk back onto the tenant even when a gross-up exists. Insist on all three of the following:

• Your pro-rata share is your rentable square footage divided by the building's total rentable square footage, written into the lease as a fixed percentage — for example, 5,000 / 100,000 = 5.00%. That number appears in black and white and does not float.
• The denominator is never "occupied square footage" or "leased square footage." An occupied-area denominator is the mirror image of the shrinking-denominator abuse: as suites empty, your fixed costs get divided across a smaller base and your percentage climbs automatically, even for expenses that shouldn't move.
• If the building is physically expanded, reconfigured, or re-measured (BOMA re-measurements can quietly add rentable square footage), your percentage is recalculated transparently and proportionally, not adjusted at the landlord's sole discretion.

Pairing a total-rentable denominator with a 95% variable gross-up is what makes a lease genuinely vacancy-proof. The gross-up stops the landlord from inflating variable costs against a small base; the fixed-percentage denominator stops them from inflating your *share* of any cost. One without the other leaves a gap. A common trap is a lease that touts a gross-up clause in the operating-expense section while defining pro-rata share on occupied area three pages later — the two clauses fight each other, and the tenant loses. Read both sections together before signing.

Base-year traps and grossed-up base years

Many office leases — especially full-service or modified-gross structures — don't bill CAM as a straight pass-through. Instead they use a base year: a benchmark year (often the calendar year of, or the first twelve months after, lease commencement) whose operating expenses set your floor. You then pay only the *increase* in expenses above that base-year amount. It sounds tenant-friendly, and it can be — but vacancy quietly weaponizes it against you if you don't watch the occupancy level in the base year.

Here's the mechanism. Suppose the building is only 50% occupied in your base year. Total CAM that year is $500,000, so the base-year expense pool the landlord records is artificially *low*, because half the building is dark and running cheap. Two years later the building climbs to 90% occupancy, and total CAM rises to $550,000 — a modest 10% increase in real spending. But because your base year captured a half-empty, low-cost building, the *gap* between current expenses and that depressed base is large, and you get billed on that inflated gap. In effect, you end up funding the ordinary cost of the landlord filling their own building, even though per-square-foot efficiency barely changed.

The fix is a grossed-up base year. Negotiate language requiring the landlord to compute what base-year CAM *would have been* at 95% occupancy, and use that higher, normalized figure as your benchmark. Now future occupancy-driven cost increases don't masquerade as expense inflation, because your base already assumes a near-full building. This is standard in institutional and Class-A office leases, and most sophisticated landlords will accept it if you raise it early in negotiation. If a landlord resists, the plain-English argument is hard to rebut: without a grossed-up base year, the tenant is subsidizing the landlord's leasing risk and being charged for the cost of the landlord earning more rent. Get the gross-up applied to both the base year and each comparison year so the two sides of the equation are measured on the same occupancy assumption — a base-year gross-up with no comparison-year gross-up (or vice versa) reintroduces the very distortion you're trying to remove.

Capping and auditing your vacant-space exposure

Two more protections turn the gross-up and exclusions from theory into enforceable dollars: a properly written cap and an audit right with teeth.

Caps. A blunt "CAM increases capped at 4% annually" is weak, because it still lets the landlord pass vacancy costs through as long as the total stays under the ceiling. What you want is either a vacancy-specific cap — language stating that operating expenses attributable to vacant space shall not exceed the same per-square-foot amount charged to occupied space — or a hard cap on controllable expenses combined with a floor that says the landlord cannot bill you more than a fully occupied building would generate per square foot. Concretely: if occupied space pays $8.00/sq ft in CAM and the landlord tries to bill $12.00/sq ft because fewer tenants are splitting the pool, a vacancy cap locks your rate at $8.00. Vacancy caps are common in multi-tenant office leases but rare in retail, so retail tenants must push harder. In soft markets — U.S. office vacancy ran roughly 15–20% in 2023–2025 — landlords eager to retain tenants concede these terms more readily than they will admit.

Audits. None of the above matters if you can't verify the math, so pair every gross-up with an annual (ideally quarterly) audit right. Weak audit clauses limit you to "reasonable" requests once a year and make you pay unless errors exceed 5%. Strengthen it: require the reconciliation to show the gross-up calculation explicitly — the occupancy assumption used and the specific variable costs adjusted — and to provide a schedule listing each vacant suite's square footage and the expenses allocated to it. Add an error-shift clause: if the audit finds overcharges above 3–5%, the landlord pays for the audit. Real audits routinely recover 5–10% of billed CAM, with gross-up and vacancy-allocation errors among the most frequent findings. Quarterly statements let you catch a spike early — a "janitorial" line jumping from $1.50 to $2.80 per square foot because an empty floor got added to the cleaning contract — rather than discovering it a full year late. BOMA's operating-expense standards give you an external benchmark to flag a building billing well above market.

Related questions

What occupancy percentage should the gross-up use?

Push for 95%, applied only to variable expenses. At 100%, the landlord normalizes costs to a fully occupied building that may never exist, slightly overcharging you every year. Fixed costs like taxes and insurance shouldn't be grossed up at all, since they don't move with occupancy.

Does a gross-up ever hurt the tenant?

Yes — when it's set at 100%, applied to fixed costs, or paired with an occupied-area denominator. A poorly drafted gross-up can overstate expenses. The protective version is 95%, variable-only, combined with a fixed pro-rata percentage of total rentable area.

Can I just refuse a gross-up clause entirely?

You can, but it usually backfires in multi-tenant buildings, because without one the landlord can spread variable costs across only the paying tenants during high vacancy — the exact spike you're trying to avoid. A correctly written 95% gross-up protects you better than no clause at all.

How much can vacancy pass-throughs cost me?

On a 5,000-square-foot suite, mishandled vacancy allocation commonly runs $8,000–$15,000 a year during a downturn. Over a multi-year term that compounds into tens of thousands, which is why the clause and the annual audit both matter.

Do these protections apply to retail as well as office?

The principles apply everywhere, but retail leases resist vacancy caps and gross-ups more than office leases do. Retail tenants often must fight harder for exclusions and audit rights, and should scrutinize "controllable vs. uncontrollable" CAM definitions especially closely.

FAQ

Can I negotiate a gross-up clause to protect me from vacant-space costs? Yes. A correctly written gross-up adjusts variable expenses as if the building were 95% occupied, which stops the landlord from dividing real costs across only the paying tenants. Cap the occupancy assumption at 95%, apply it to variable costs only, and pair it with a fixed pro-rata percentage of total rentable area.

What if the landlord refuses to change the gross-up language? Ask for a compromise: a lower gross-up percentage, a hard CAM cap, or a "no vacant-space cost" addendum excluding leasing commissions, marketing, and other-tenant improvements. In soft markets landlords concede more to retain tenants, so raise these points early and be ready to trade on other terms.

Are there ways beyond the gross-up to avoid paying for empty suites? Yes. Exclude vacancy-driven costs outright — commissions, marketing, capital expenditures, and tenant improvements for other suites. Add a vacancy-specific cap, negotiate a grossed-up base year in base-year leases, and secure an audit right so you can verify no excluded items slipped into the pool.

Does the type of CAM expense matter for vacancy exclusions? Very much. Fixed costs — property taxes, insurance, the management base fee — barely move with occupancy and shouldn't be grossed up. Variable costs — janitorial, utilities, landscaping — scale with occupancy and are where the gross-up applies. Negotiate the treatment separately for each bucket rather than accepting one blanket formula.

How do I make my pro-rata share resistant to vacancy? Define your share as your rentable square footage divided by the building's total rentable square footage, written as a fixed percentage. Never accept an "occupied area" denominator, which automatically raises your percentage as suites empty. Combined with a 95% gross-up, a fixed-percentage denominator makes vacancy unable to inflate your bill.

Can I challenge CAM charges in a high-vacancy multi-tenant building after signing? Only if your lease includes an audit or dispute right, which is why you negotiate it up front. Request a detailed reconciliation showing the gross-up occupancy assumption and every vacant-suite allocation. If you find errors — inflated gross-ups, excluded items, or costs that belong to the landlord — you can force a correction and often recover past overpayments.

Sources

• https://www.cbre.com/insights
• https://www.us.jll.com/en/views
• https://www.cushmanwakefield.com/en/united-states/insights
• https://www.boma.org/BOMA/Research-Resources/
• https://www.naiop.org/research-and-publications/
• https://www.irem.org/learning/
• https://www.nolo.com/legal-encyclopedia/commercial-real-estate-leases
• https://www.investopedia.com/terms/t/tripe-net-lease-nnn.asp

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