Single Net Lease Explained: N Lease Definition, Tenant Obligations, and Why It's Rare
Quick Answer
A single net lease (N lease) has the tenant paying base rent plus property taxes only. The landlord covers insurance, CAM, maintenance, and structural costs. Single-net is the rarest net lease type—it creates an awkward risk split and has been largely displaced by NNN in modern commercial real estate.
If you encounter a single-net lease in a due diligence file or an older property you're taking over, it's almost certainly a legacy document. Here's what it means, how it works, and why you won't see many new ones being written today.
What the Single Net Lease Actually Means
The "single" in single-net refers to one expense category that the tenant takes on: property taxes. That's it.
| Expense Category | Tenant's Obligation | Landlord's Obligation |
|---|---|---|
| Base rent | Yes | — |
| Property taxes | Yes | — |
| Building insurance | No | Yes |
| CAM (maintenance, landscaping, janitorial) | No | Yes |
| Structural repairs | No | Yes |
| HVAC maintenance and replacement | No | Yes |
| Utilities (common areas) | No | Yes |
| Management fees | No | Yes (absorbed) |
The landlord pays for everything except property taxes. Under a 50,000 SF building with $1.80/SF in insurance costs and $4.20/SF in operating/maintenance costs, the landlord is absorbing $300,000/year in costs while passing through only the tax line.
Why the Risk Split Is Awkward
Property taxes are the most volatile of the three major operating expense categories. They're driven by government assessment decisions, market value appreciation, and political tax policy—all completely outside the landlord's control. Insurance and CAM, while they can increase, are partially within the landlord's management influence.
Single-net creates a situation where:
- The landlord absorbs predictable-but-rising maintenance costs
- The landlord absorbs insurance costs (which have been highly volatile since 2022)
- The tenant absorbs tax increases that neither party can control or predict
This is backwards from a risk management perspective. NNN leases pass all three categories to tenants, creating clean incentive alignment. Gross leases price everything in, creating cost certainty. Single-net does neither—it creates an ambiguous middle ground where the landlord has significant expense exposure without the simplicity of a gross structure.
Comparing N, NN, and NNN Side-by-Side
| Feature | Single-Net (N) | Double-Net (NN) | Triple-Net (NNN) |
|---|---|---|---|
| Tenant pays: taxes | Yes | Yes | Yes |
| Tenant pays: insurance | No | Yes | Yes |
| Tenant pays: CAM | No | No | Yes |
| Landlord exposure | High | Moderate | Low |
| CAM reconciliation | No | No | Yes |
| Modern prevalence | Rare | Uncommon | Dominant (retail/industrial) |
For the double-net comparison, see double net lease explained. For the NNN deep dive, see NNN lease vs gross lease.
How Property Tax Billing Works Under Single-Net
The mechanics are the same as any net lease tax allocation:
- Landlord receives the annual property tax bill (timing varies by municipality—typically Q3 or Q4)
- In multi-tenant buildings, the bill is allocated by pro-rata share (tenant SF ÷ total building SF × annual tax)
- The landlord bills the tenant their proportionate share—either as a monthly estimate collected throughout the year, or as a lump sum after receiving the actual bill
- Year-end reconciliation adjusts for any difference between estimates and actuals
Worked example: Building with 40,000 SF total leasable area. Annual property tax: $168,000 ($4.20/SF). A single-net tenant with 6,000 SF has a 15% pro-rata share: $25,200/year in taxes, billed at $2,100/month.
If the county reassesses the property mid-lease and taxes jump to $5.10/SF, the tenant's obligation increases to $30,600/year with no cap protection—property taxes are non-controllable regardless of lease type.
Where Single-Net Leases Still Appear
Single-net leases aren't extinct—they're just concentrated in specific contexts:
Legacy industrial leases: Industrial properties in manufacturing-heavy markets (Midwest, Southeast) often have older leases drafted in the 1980s–1990s with N structures. Renewal negotiations typically push toward NN or NNN.
Ground leases: Ground leases sometimes have the ground tenant (who owns the improvements) pay property taxes while the ground landlord (who owns the land) handles other costs—creating a de facto single-net arrangement.
Very small single-tenant properties: A small freestanding retail building of under 3,000 SF where the landlord knows the tenant personally and wants simplicity may use single-net to avoid the complexity of full NNN billing.
Percentage lease hybrids: Some retail percentage leases combine a low base rent with single-net tax pass-through, keeping the operating structure simple while still participating in tenant revenues.
Converting Single-Net to a Standard Lease Structure
If you're managing a portfolio with single-net leases and working toward standardization, the conversion to NNN or modified-gross typically happens at lease renewal. The considerations:
Establish baseline expense data. Before transitioning a tenant to NNN, you need historical expense records to set realistic CAM estimates. If the landlord has been absorbing all CAM costs without detailed tracking, there may be a gap in the data needed to set first-year NNN estimates.
Assess tenant leverage. In high-vacancy markets, tenants may resist moving from N to NNN—adding $4–6/SF in CAM obligations on top of their existing tax obligation is a significant increase. Landlords may need to reduce base rent to offset.
Review the existing lease for conversion provisions. Some older leases include clauses addressing what happens at renewal with respect to lease structure. These provisions can either facilitate or complicate conversion.
For the full context of how single-net fits within the broader commercial lease landscape, see the commercial lease types guide, the commercial lease rent structures overview, and gross lease vs net lease.
The Bottom Line on Single-Net Leases
Single-net leases are a relic of an era when CRE transactions were less sophisticated and expense allocation conventions hadn't standardized around NNN. They persist in legacy portfolios and specific niche situations, but new single-net leases are uncommon.
If you're underwriting a property with single-net tenants, model the landlord's ongoing CAM and insurance exposure carefully—those costs will grow regardless of what the tenant pays, and there's no recovery mechanism until the lease renews. The cam variance analysis framework helps quantify that exposure even when it's not a billable reconciliation item.
For NNN investment property analysis and how to evaluate properties with mixed lease structures, see those guides next.