Gross lease abstraction is the process of pulling the terms that decide who actually pays for what out of a full service gross or modified gross lease: base rent, the base year or expense stop, which services the landlord provides, and which operating expenses still pass through to the tenant. Gross leases look simple because the tenant writes one check. The complexity is buried in the expense mechanics, and that is where the money is. A base year defined one clause later than you assumed can swing a reconciliation by six figures. Upload a lease below to abstract it free, no signup required.
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Lease type labels are used loosely in the market, and the label on the cover page tells you very little. What matters is the expense clause. This is how the six common structures allocate the operating costs of a building, and what an abstract has to capture for each so a reconciliation can be checked rather than trusted. Note that a lease calling itself modified gross can behave almost like a net lease depending on where the base year sits.
| Lease structure | Property taxes | Building insurance | CAM and maintenance | Utilities | Roof and structure | What the abstract must capture |
|---|---|---|---|---|---|---|
| Gross lease | Landlord | Landlord | Landlord | Landlord | Landlord | Base rent, escalation schedule, and exactly which services the rent includes |
| Full service gross (FSG) | Landlord | Landlord | Landlord | Landlord | Landlord | Base year, the expense categories in the base, and after-hours HVAC charges billed on top |
| Modified gross (MG) | Negotiable | Negotiable | Shared | Often tenant | Landlord | Base year or expense stop, pro rata share, which categories pass through, caps and exclusions |
| Industrial gross | Often tenant | Often tenant | Tenant | Tenant | Landlord | The specific carve-outs, since the label is regional and means different things in different markets |
| Triple net (NNN) | Tenant | Tenant | Tenant | Tenant | Usually landlord | Pro rata share, expense exclusions, caps, audit rights, and the landlord structural carve-out |
| Absolute net (bondable) | Tenant | Tenant | Tenant | Tenant | Tenant | That there are genuinely no landlord obligations, which is rarer than the label suggests |
The tenant pays one number, so people assume there is nothing to abstract. Then the first annual reconciliation arrives and nobody can reconstruct what the base year was supposed to include. These are the terms that decide the outcome.
Base year is the calendar or lease year whose operating expenses are baked into the rent. Only increases above it pass through. Which year, and whether it is a calendar or fiscal year, is the single most valuable field in a full service gross abstract.
A modified gross lease often uses a fixed dollar stop per square foot instead of a base year. Above the stop, the tenant pays its share. Capture the stop, the year it applies from, and whether it is grossed up.
Whether management fees, capital expenditures, and property taxes sit inside or outside the expense pool is negotiated clause by clause. This list is what makes a reconciliation auditable instead of a matter of trust.
The tenant share is a fraction of building rentable area, and both the numerator and denominator get amended. An expansion that never made it into the abstract means every subsequent reconciliation is billed on the wrong percentage.
Caps on controllable expenses, gross-up provisions, and the tenant right to audit the landlord books are the tenant protections that only exist if someone reads them. Most are never exercised because nobody knew they were in the lease.
Clean Excel, CSV, and JSON, plus an API, so base years, stops, and shares land in Yardi, MRI, or your reconciliation model without re-keying.
From a signed full service gross lease to a reconciliation you can actually check.
Add the original lease, any amendments touching the expense clause, and the exhibit listing operating expense inclusions. The exhibit is usually where the real definition of the expense pool lives.
The model pulls base rent and escalations, the base year or expense stop, the pro rata share, the operating expense inclusions and exclusions, any caps, gross-up language, and the tenant audit right.
Every extracted field links to its source page, so you verify that the base year is the year you think it is and that management fees are where you think they are, in minutes rather than by re-reading the lease.
Push the abstract into Excel, CSV, or JSON and use it to check the landlord reconciliation statement line by line, against the lease language rather than against last year.
Last updated July 2026. What a gross lease is, how full service gross and modified gross differ, and which fields an abstract has to capture to make a reconciliation checkable.
A gross lease is a commercial lease in which the tenant pays a single rent figure and the landlord pays the operating costs of the property: property taxes, building insurance, common area maintenance, and usually utilities. The tenant gets budget certainty and the landlord takes the expense risk, pricing that risk into a higher base rent. Gross leases are common in multi-tenant office buildings, where separating one tenant share of a shared HVAC plant would be impractical, and they are considered the more tenant-friendly structure because the rent is predictable.
The difference is who carries the risk that operating expenses rise. In a gross lease the landlord pays the property expenses out of the rent it collects, so an unexpected tax reassessment is the landlord problem. In a net lease the tenant pays those expenses on top of base rent, so the same reassessment lands on the tenant. A triple net lease pushes taxes, insurance, and maintenance to the tenant, and the fields that structure carries are set out in NNN lease abstraction. The middle ground, modified gross, splits them. Base rent in a gross lease is therefore always higher than the base rent in an otherwise identical net lease, and comparing the two on headline rent alone is meaningless.
A full service gross lease is a gross lease where the quoted rent covers essentially everything: taxes, insurance, maintenance, utilities, and janitorial service. It is the standard structure in institutional office space. The catch is that full service almost never means fully fixed for the whole term. Nearly every full service gross lease establishes a base year, and from the second year forward the tenant pays its pro rata share of the increase in operating expenses over that base year. Tenants who believe full service means one number forever are the ones surprised by their first reconciliation statement. After-hours HVAC is also typically billed separately, at a rate stated in the lease.
A modified gross lease is a hybrid where the parties negotiate which operating expenses stay with the landlord and which pass through to the tenant. It is the most flexible structure and the least standardized, so the label tells you almost nothing. A modified gross lease might mean the rent covers everything except electricity and janitorial. It might mean the tenant pays its share of every expense above a fixed dollar stop. Because the term is used so loosely across US markets, the only reliable way to know what a modified gross lease requires is to read its expense clause and its exhibits, which is precisely the work an abstract exists to capture.
The base year is the year of operating expenses that is included in the base rent. In later years the tenant pays its pro rata share of expenses only to the extent they exceed that base year amount. If the base year is 2026 and building expenses run $12.00 per square foot that year, a tenant occupying ten percent of the building pays ten percent of anything above $12.00 in 2027 and beyond. Two details decide whether that math is fair. First, whether the base year is a calendar or lease year. Second, whether the base year expenses were grossed up to full occupancy, because a base year set while the building was half empty produces an artificially low baseline and years of inflated pass-throughs. Our explainers on the base year and the gross-up provision work through the arithmetic.
An expense stop is a fixed dollar amount per square foot of operating expenses that the landlord absorbs, with the tenant paying its share of everything above it. It does the same job as a base year but states the number directly instead of deriving it from a year of actual costs. A stop of $11.50 per square foot means the tenant pays its pro rata share of expenses above $11.50, regardless of what the building actually spent in any base year. Stops are cleaner to administer and easier to abstract, and they remove the gross-up argument entirely, which is why tenants often prefer them.
Neither, once the rent is priced correctly. A gross lease gives the tenant a predictable occupancy cost and gives the landlord a higher base rent for absorbing expense volatility. A net lease does the reverse. What actually decides the outcome is the expense clause: a gross lease with a badly set base year can cost a tenant more over a ten year term than a net lease would have, and a landlord who granted a generous expense stop in a year of rising insurance premiums will feel it. The structure is a risk allocation, not a discount, and the abstract is how you find out which way the risk actually runs.
Base rent and the escalation schedule, the base year or expense stop and whether it is calendar or fiscal, the tenant pro rata share with the rentable area figures behind it, the definition of operating expenses with every inclusion and exclusion, any cap on controllable expenses, the gross-up provision, the tenant audit right and its deadline, and the services the landlord is obligated to provide including after-hours HVAC rates. Miss the exclusions list and you cannot challenge a reconciliation. Miss the audit deadline and the right expires. These fields belong in every abstract, and our commercial lease abstract template lays out the full field set.
The AI reads the lease and its exhibits, identifies the expense structure regardless of what the cover page calls it, and pulls the base year, stop, share, inclusions, exclusions, caps, and audit rights as structured fields, each linked to the page it came from. That page citation matters more here than almost anywhere else in lease abstraction, because the arguments in a reconciliation are arguments about definitions, and a reviewer needs to read the actual clause. What AI removes is the hours spent finding the operating expense exhibit in a hundred page document. What it does not remove is judgment about whether an ambiguous exclusion covers a particular cost, which is why every extracted field cites its source. Upload a lease above to see the output on your own document, or read the full lease abstraction software overview.
Still have questions? Our team is happy to help.
Talk to our teamA gross lease is a commercial lease where the tenant pays one rent figure and the landlord pays the property operating costs: taxes, insurance, common area maintenance, and usually utilities. The tenant gets predictable occupancy cost, the landlord takes expense risk and prices it into a higher base rent. It is common in multi-tenant office buildings.
Who carries the risk that operating expenses rise. In a gross lease the landlord pays property expenses out of the rent collected. In a net lease the tenant pays them on top of base rent. Base rent in a gross lease is therefore always higher than in an otherwise identical net lease, so comparing headline rents alone is meaningless.
A full service gross lease quotes a rent covering taxes, insurance, maintenance, utilities, and janitorial. It is standard in institutional office space. It rarely means fixed forever: most establish a base year, and from year two the tenant pays its pro rata share of expense increases above it. After-hours HVAC is normally billed separately.
A modified gross lease is a hybrid in which the parties negotiate which operating expenses the landlord keeps and which pass through to the tenant. It is the least standardized structure, so the label alone tells you nothing. The only reliable way to know what it requires is to read the expense clause and its exhibits.
The base year is the year of operating expenses included in base rent. Afterward the tenant pays its share of expenses only above that amount. Two details decide fairness: whether it is a calendar or lease year, and whether base year expenses were grossed up to full occupancy. A base year set while a building was half empty inflates pass-throughs for the rest of the term.
Both set the baseline the landlord absorbs. A base year derives it from actual expenses in a specified year. An expense stop states a fixed dollar amount per square foot directly, such as $11.50. Stops are simpler to administer and remove the gross-up argument entirely, which is why many tenants prefer them.
Neither is better once rent is priced correctly. A gross lease buys the tenant predictability and pays the landlord for absorbing expense volatility. A triple net lease does the reverse. The structure is a risk allocation, not a discount, and the expense clause decides which way the risk actually runs.
The net lease side: recoveries, caps, and landlord carve-outs.
Learn moreWhere expense reconciliations go wrong, and how to catch it.
Learn morePull the expense clauses and exclusions out of the exhibits.
Learn moreBase years and pro rata shares that reconcile.
Learn moreEvery field a complete lease abstract should capture.
Learn moreAmendments that move the base year and pro rata share.
Learn moreThe full overview of our AI lease abstraction tool.
Learn more