A modified gross lease is a commercial lease that splits operating costs between landlord and tenant, sitting between a full service gross lease and a triple net lease. The tenant pays a base rent that covers an agreed set of expenses in the first year, and then pays its share of any increases above that first-year "base" amount in later years. It is the most common structure in multi-tenant office buildings, precisely because it gives the tenant a predictable rent while protecting the landlord from rising costs over the term.
What a modified gross lease means
The word "modified" is doing the work. A pure gross lease bundles everything into rent; a triple net lease strips everything out and bills it separately. A modified gross lease is a negotiated middle: the landlord keeps some costs, the tenant takes others, and the exact split is spelled out in the lease rather than implied by the label.
In the typical version, the landlord pays the operating expenses in the base year (usually the first year of the term), and the tenant reimburses its pro-rata share of the amount those expenses rise above the base year in every year after. That mechanism is called an expense stop or base year stop, and it is the heart of the structure.
Who pays what in a modified gross lease
There is no single fixed split; it is whatever the lease says. A common arrangement looks like this:
| Cost | Who typically pays |
|---|---|
| Base rent | Tenant |
| Property taxes and insurance | Landlord to the base year; tenant pays its share of increases |
| Common area maintenance | Landlord to the base year; tenant pays its share of increases |
| In-suite utilities and janitorial | Often the tenant directly |
| Structure and roof | Landlord |
Because the details vary so much, two leases both called "modified gross" can allocate costs very differently. The only reliable way to know what a tenant actually owes is to read the operating-expense and base-year clauses, not the deal label.
How the base year works
The base year sets the landlord's cost baseline. Suppose the building's operating expenses run $8.00 per square foot in the base year. The landlord absorbs that $8.00 for the life of the lease. If expenses rise to $8.60 in year two, the tenant pays its share of the $0.60 increase; the landlord still covers the original $8.00.
Two things make or break this clause for a tenant. First, the base year should reflect a fully occupied, fully operational building, or the landlord should gross up variable costs to that level, otherwise the base is artificially low and the tenant overpays on increases from day one. Second, the landlord tracks actual operating costs each year to compute the increase, so both sides need the same underlying expense records; landlords who turn the operating-expense invoices into a clean expense record can support the year-end statement without a scramble. A tenant should always keep the right to audit that statement.
Modified gross vs full service vs triple net
The three structures differ only in who carries the operating costs and how visibly.
| Lease type | How operating costs are handled |
|---|---|
| Full service gross | Landlord pays all operating costs out of one rent |
| Modified gross | Landlord pays to a base year; tenant pays its share of increases |
| Triple net (NNN) | Tenant pays taxes, insurance, and CAM in full, on top of rent |
A modified gross rent looks higher than an NNN quote at first glance, but that is because it already includes the base-year expenses. To compare a modified gross offer against an NNN one, you have to normalize both to an all-in cost per square foot, the same reconciliation an accurate lease abstract is built to support.
What to abstract from a modified gross lease
The value and the risk sit in a few specific clauses. Capture these when you abstract one:
- The base year and exactly which expense categories it covers.
- The gross-up provision and the occupancy level costs are grossed up to.
- The tenant's pro-rata share and the denominator behind it.
- Any cap on controllable expense increases.
- The reconciliation and audit-rights window, so a tenant can check the year-end statement in time.
These are the same recovery mechanics a landlord needs for a defensible CAM reconciliation and a tenant needs for a lease audit. Leaseabstracts pulls each one from the lease PDF, source-linked to the clause.
Modified gross lease FAQ
What is a modified gross lease?
A modified gross lease is a commercial lease that splits operating costs between landlord and tenant. The landlord covers an agreed set of expenses in the base year, and the tenant pays base rent plus its share of any increase in those expenses above the base-year amount in later years. It sits between a full service gross lease and a triple net lease.
What is the difference between modified gross and triple net?
In a triple net lease the tenant pays taxes, insurance, and CAM in full on top of rent, from the first dollar. In a modified gross lease the landlord pays those costs up to a base year and the tenant only pays its share of the increases above it. Modified gross gives the tenant more predictable costs; triple net shifts more risk to the tenant.
What does modified gross mean for rent?
It means the quoted rent already includes the landlord's base-year operating costs, so the headline number is higher than a triple net quote but closer to the all-in cost. On top of that rent, the tenant pays only its pro-rata share of expense increases above the base year, not the full operating cost.
Is a modified gross lease better for the tenant?
It is often more predictable for the tenant than triple net, because the landlord absorbs the base-year costs and the tenant is exposed only to increases. Whether it is cheaper depends on the base year and the gross-up: a low or ungrossed base year quietly raises the tenant's share of increases, so the clause matters more than the label.