A modified gross commercial lease splits building operating costs between landlord and tenant instead of loading them onto one side. The tenant pays a single base rent that already covers some of the landlord’s expenses, then picks up one or two additional categories directly, often utilities, janitorial, or interior maintenance. It sits between a full-service gross lease, where the landlord bundles everything into the rental rate, and a triple net lease, where the tenant pays property taxes, insurance, and maintenance on top of rent. Getting one right is almost entirely about the expense allocation: which costs are in the base rent, which the tenant pays separately, and how increases over time get divided.
How the Expense Split Actually Works
Base rent in this structure is stated as a monthly dollar amount or a price per square foot per year, and the number only makes sense once you know what it includes. One lease might fold taxes, insurance, and common area maintenance into the base rent while the tenant pays utilities. Another might include only taxes, leaving insurance and janitorial costs to the tenant. The defining feature of the modified gross structure is that the allocation varies deal to deal, so read the expense section line by line before you accept a rent figure.
Alongside the categories built into base rent, the lease sets rules for how operating cost increases pass through to you over the term. That is where most tenant losses happen. Two mechanisms show up in nearly every form: the base year and the expense stop.
Base Year
A base year clause fixes the first full calendar year of the lease as the benchmark. The landlord covers all operating expenses during that year. In every year after, you pay a pro-rata share of any increase above the base year amount. Your pro-rata share is your rentable square footage divided by the total rentable square footage of the building. A 5,000-square-foot suite in a 50,000-square-foot building carries a 10 percent share. If base year operating expenses are $200,000 and climb to $220,000 the following year, you owe 10 percent of the $20,000 increase, or $2,000. These year-over-year adjustments are commonly called escalation clauses.1Practical Law. Modified Gross Lease
Expense Stop
An expense stop works the same way but without tying to a specific calendar year. The landlord sets a fixed dollar-per-square-foot threshold based on historical data, and anything above that number passes through to tenants. The mechanical effect is identical to a base year; the number just comes from negotiation rather than whatever expenses happen to land in year one.
Gross-Up Clauses
If the building is not fully occupied when your base year begins, actual operating expenses will be artificially low because fewer tenants are generating utility, janitorial, and management costs. A gross-up clause adjusts variable expenses upward to reflect what they would be at a specified occupancy level, usually 95 percent. Without the gross-up, your base year number is deflated, and you start paying escalations sooner as the building fills up, even though per-tenant costs haven’t actually risen. Only variable costs like electricity, trash removal, and cleaning should be grossed up. Fixed costs like property taxes and insurance do not change with occupancy and should be excluded.
What Should Not Be in Operating Expenses
Not every dollar the landlord spends on the building should flow through to tenants. The exclusion list is where tenants protect themselves from charges that reflect the landlord’s investment decisions or business overhead rather than building operations. Negotiate these out of the expense pool before signing:
- Capital improvements, including structural repairs, roof replacement, and building upgrades that add long-term value.
- Leasing costs, including broker commissions, advertising, and tenant improvement allowances for other tenants’ spaces.
- Debt service, including mortgage principal and interest, ground lease payments, and financing fees.
- Landlord entity expenses, including executive salaries above the building manager level, legal fees for enforcing other tenants’ leases, and political or charitable contributions.
- Penalties and fines resulting from the landlord’s own noncompliance.
- Costs already reimbursed by the landlord’s insurance proceeds.
- Above-market management or service fees paid to the landlord’s affiliated companies.
If the form you are completing does not include these exclusions in its boilerplate, add them as a rider or exhibit before signing. The landlord’s willingness to accept exclusions tells you a lot about how the building will be managed.
Audit Rights
Exclusions only matter if you can verify what the landlord is billing. The form should give you the right to review the books and records supporting any operating expense increase. A workable audit clause specifies how far back you can look, how much notice you must give, and where the inspection takes place. Many clauses limit audits to once per year and require that you hire a CPA rather than a contingency-fee auditor. If the audit reveals an overcharge above a negotiated threshold, commonly 3 to 5 percent, the landlord typically reimburses your audit costs on top of refunding the overcharge.
Maintenance and Repair Allocation
Physical upkeep is divided between the parties, and the form includes designated fields or check-boxes for each category. The landlord typically handles structural components: roof, foundation, exterior walls, and building-wide systems like elevators and fire suppression. The tenant takes responsibility for the interior of the leased space, including day-to-day plumbing, electrical, and HVAC servicing within the suite. Janitorial service and interior cleaning almost always fall to the tenant.
Watch the distinction between who performs the work and who pays the invoice. A lease might assign HVAC maintenance to the tenant while requiring the landlord to reimburse repair costs above a stated dollar cap.
HVAC Replacement
The most common maintenance dispute in commercial leases involves HVAC replacement. A rooftop unit serving a single suite can cost tens of thousands of dollars to replace, and the question of who pays depends entirely on what the lease says. If the tenant is responsible for all HVAC costs, a system failure in year eight of a ten-year lease produces a massive expense with only two years of benefit. A fairer approach is a proration based on remaining lease term: the landlord pays for the replacement, and the tenant reimburses a proportionate share covering only the years left on the lease. That structure also gives the tenant an incentive to authorize the replacement instead of repeatedly patching an aging unit.
Term, Rent, and Escalation
Every lease form requires a commencement date, an expiration date, and the base rent amount. The commencement date is not always the day you sign. It often ties to a specific trigger like substantial completion of tenant improvements or issuance of a certificate of occupancy. Make sure the form defines what starts the clock, and consider negotiating a rent abatement period if you need time to build out the space before opening.
Most modified gross leases include an annual rent escalation. Two approaches are standard. A fixed percentage increase, often 2 to 4 percent per year, is simpler and more predictable. A CPI-based adjustment tracks inflation more closely but can produce unpleasant surprises in high-inflation years. Some tenants negotiate a CPI adjustment with a cap, so the annual increase never exceeds a set ceiling regardless of what the index does.
Premises Description and Square Footage
Because both your rent and your pro-rata expense share depend on it, the square footage figure on the lease deserves independent verification. The premises description needs three elements: the street address, the suite or unit number, and the total rentable square footage.
Rentable area in office buildings is typically calculated under BOMA International’s measurement standard, currently ANSI/BOMA Z65.1-2024, which determines how shared corridors, lobbies, and restrooms are allocated across tenants.2BOMA International. BOMA Standards The rentable figure will always be larger than the space you actually occupy because it includes your proportionate share of common areas. Verify the number rather than taking it from marketing materials. Some markets, including New York City, follow local real estate board standards instead of BOMA, so confirm which methodology applies.
The property’s tax parcel number should also appear in the premises section, confirmable through your county tax assessor’s records. Getting this wrong means the lease may not attach cleanly to the legal title, which surfaces during financing, sale, or any dispute where the property description matters.
Use the landlord’s and tenant’s full legal names exactly as they appear on their formation documents. A mismatch between the name on the lease and the name on the entity’s state filing can create enforcement headaches later.
Security Deposits, Letters of Credit, and Guaranties
Commercial security deposits are far less regulated than residential ones. The amount is negotiable in most jurisdictions, with deposits ranging from one to six months’ rent depending on the tenant’s financial strength. Commercial landlords are generally not required to hold the deposit in an interest-bearing account or return it within a short statutory window. The lease controls what constitutes a default that triggers the deposit, whether the landlord can apply it to unpaid rent during the lease, and the timeline for return after the lease ends.
Tenants with strong banking relationships sometimes offer a standby letter of credit instead of tying up cash. The money stays in the tenant’s account while giving the landlord the same security; the landlord draws on the letter only if the tenant defaults. If the form includes a letter of credit option, confirm the bank’s requirements for collateral, renewal terms, and what happens if the issuing bank fails.
When the tenant is a newly formed LLC or a single-purpose entity, expect the landlord to require a personal guaranty from a principal, usually as a separate document attached as an exhibit. A full guaranty makes the individual liable for every obligation under the lease. A limited or “good guy” guaranty caps the exposure, for example covering rent only through the date the tenant surrenders the space.
Insurance and Waiver of Subrogation
The insurance section specifies which policies each party must carry and the minimum coverage amounts. The landlord generally maintains property insurance on the building structure and common areas. The tenant carries commercial general liability insurance for injuries and property damage within the leased premises, along with contents or business personal property coverage.
One clause worth understanding before you check the box is the mutual waiver of subrogation. Subrogation is an insurer’s right to recover from a third party after paying a claim. If a fire starts in the tenant’s suite and damages the landlord’s building, the landlord’s insurer would normally seek reimbursement from the tenant. A waiver of subrogation prevents that: both sides agree their carriers will not pursue the other party for covered losses. Most standard forms include this waiver and most commercial insurers accept it, but confirm with your carrier before signing.
Use, Assignment, and Subletting
The permitted use clause defines what the tenant can do in the space. It might be broad (“general office use”) or narrow (“medical dermatology practice”). A clause that is too narrow can make the space difficult to assign or sublet later, so negotiate language covering your current operations and any reasonable expansion.
Retail tenants in multi-tenant buildings should also negotiate an exclusive use clause preventing the landlord from leasing other space in the same property to a direct competitor. Vague language about “similar” businesses invites disputes. Specify the product or service category, define the geographic scope within the property, and address whether existing tenants are grandfathered in.
Almost every commercial lease requires the landlord’s written consent before assignment or subletting. The key is the standard governing that consent. A sole discretion clause lets the landlord refuse for any reason. A reasonableness standard requires a legitimate business reason, such as the proposed assignee’s poor credit or an incompatible use. Push for reasonableness and try to include objective criteria the landlord will use when evaluating a transfer. Most forms also include a recapture right, which lets the landlord terminate the lease and take back the space rather than approve an assignment. The original tenant typically remains liable for all lease obligations even after a permitted assignment, unless the landlord agrees to a release, which is rare.
Default, Cure Periods, and Remedies
Monetary defaults, meaning unpaid rent, usually trigger a short cure window of five to ten business days after written notice. Non-monetary defaults such as failing to maintain insurance or violating the use clause typically allow a longer cure period of around thirty days. If the non-monetary default cannot reasonably be fixed in thirty days, many leases grant additional time as long as the tenant has begun the cure and is diligently pursuing it.
When the tenant fails to cure, remedies generally include terminating the lease and recovering possession, suing for damages, or both. Some leases include a rent acceleration clause making the entire remaining rent balance due immediately upon default. Courts scrutinize these provisions closely, and many require the landlord to make reasonable efforts to re-lease and credit the new rent against the accelerated amount. If the form contains an acceleration clause, check whether it includes a present-value discount; without one, the tenant effectively pays for the time value of money the landlord hasn’t yet earned.
Holdover and Relocation
If the tenant stays past the lease expiration date without a renewal, the holdover clause kicks in. Standard forms set the holdover rental rate at 150 percent of the last month’s rent, though rates anywhere from 120 to 200 percent are common. The clause may also convert the tenancy to a month-to-month arrangement terminable on short notice. Landlords want the rate high enough to discourage overstaying, while tenants want a reasonable cushion in case move-out logistics run long.
Some multi-tenant forms include a relocation clause allowing the landlord to move the tenant to a different suite. Before signing, negotiate limits:
- No more than once during the lease term.
- Not during the final two years of the lease, and only after 90 to 120 days’ written notice.
- The new suite must be equal or greater in square footage, with comparable features like window access and layout.
- The landlord covers all costs to replicate your improvements in the new space.
- The rental rate stays the same or decreases if the new space is smaller.
Without these protections, you could be forced into a smaller, less desirable suite with no recourse.
SNDAs and Estoppel Certificates
Two supplementary documents routinely attach to a modified gross lease, and the form may reference them or include them as exhibits.
A Subordination, Non-Disturbance, and Attornment agreement is a three-way contract among tenant, landlord, and the landlord’s lender. It protects the tenant’s right to stay in the space if the landlord defaults on the mortgage and the lender forecloses. Without an SNDA, a tenant whose lease is junior to the mortgage can be evicted by the foreclosure purchaser regardless of whether rent has been paid on time. The non-disturbance component is the tenant’s protection: the lender agrees not to terminate the lease as long as the tenant is not in default. In exchange, the tenant agrees to recognize the new owner as landlord. If the form gives you the right to request an SNDA, exercise it, especially in a long-term lease where ownership changes are more likely.
An estoppel certificate is a statement the tenant signs confirming basic lease facts: start and end dates, current rent, security deposit amount, any amendments, and whether either party is in default. Landlords need estoppels when refinancing or selling, because the buyer or lender wants to know what the tenants have agreed to. The form typically requires the tenant to deliver an estoppel within ten to fifteen days after written request. Review every estoppel carefully before signing; the statements you certify become binding on you even if the underlying lease says something different.
Signing and Recording
The person signing for each party must have actual authority to bind their organization. For a corporation, that means an officer: president, CEO, or an authorized vice president. For an LLC, it is typically the managing member or a manager designated in the operating agreement. If there is any doubt, ask for a corporate resolution or certificate of authority. Signing without authority can render the lease voidable.
Electronic signatures are legally valid for commercial leases under federal law. The Electronic Signatures in Global and National Commerce Act provides that a contract cannot be denied legal effect solely because an electronic signature was used in its formation.3Office of the Law Revision Counsel. 15 USC 7001 – General Rule of Validity Platforms like DocuSign and Adobe Sign create a timestamped audit trail showing who signed, when, and from what device. Make sure the executed electronic record can be retained and accurately reproduced by all parties, as the statute requires.
Recording the full lease with the county is uncommon because it exposes the financial terms to public view. Parties often record a memorandum of lease instead: a short document that puts third parties on notice of the tenant’s interest without disclosing rent or other sensitive terms. The memorandum identifies the parties, the premises, the lease term, and any significant rights like a purchase option or right of first refusal. Recording is not required for the lease to be enforceable between the parties, but it protects the tenant’s interest against a subsequent buyer who might otherwise claim no knowledge of the lease. If the form requires notarization for recording purposes, arrange that before the signing meeting. Recording fees vary by county, typically from $10 to $92 per page.
Both parties should retain a fully executed original and store digital copies in an encrypted environment separate from day-to-day business files. You will need to produce the lease quickly for estoppel requests, refinancing, disputes, or when your own lender requires a copy of all material contracts.