Net lease investing has an appealing pitch: buy a property, sign a long-term lease to a creditworthy tenant, collect predictable income with minimal management. That pitch is real — but the returns on NNN deals are pricing that simplicity in. The underwriting question is whether you are being paid enough for the risks that remain.

This article covers the full framework for analyzing a NNN lease acquisition. For a broader view of cap rate benchmarks across commercial asset classes, see What Is a Good Cap Rate for Commercial Real Estate. For multi-tenant NNN flex and retail, see How to Analyze a Flex Space Investment.

What the Three Nets Actually Mean

The term “NNN” is used loosely in the market. Understanding what each net represents helps you read the actual lease rather than relying on a broker's characterization.

Lease Type	Tenant Pays	Landlord Pays	Common Use
Gross	Base rent only	Taxes, insurance, all maintenance	Office, some residential
Modified gross	Base rent + some expenses	Some shared expenses	Multi-tenant office, flex
NN (double net)	Taxes + insurance	Maintenance / repairs	Less common; some strip retail
NNN (triple net)	Taxes + insurance + maintenance	Often structural items only	Freestanding retail, QSR
Absolute NNN	Everything including structure	Nothing	Long-term single-tenant net lease

Tenant Credit: The Most Important Underwriting Input

In a NNN deal, the lease is the asset. Its value depends primarily on how confident you can be that the tenant will pay rent through the entire term. Tenant credit is the dominant driver of both cap rate and residual risk.

Tenant Profile	Cap Rate Range	Risk Profile
Investment-grade national chain (S&P BBB- or better)	4.5%–5.5%	Near bond-like; main risk is lease expiration
Publicly traded, non-investment-grade	5.5%–6.5%	Business risk present; dark risk at expiration
Regional chain / strong local operator	6.5%–7.5%	Credit requires independent verification
Single-location local business	7.5%–10%+	High default risk; underwrite the real estate

For investment-grade tenants, you can reference public credit ratings and audited financials. For private tenants, you are evaluating the business directly — revenue, profitability, lease-to-revenue ratio, and business age all matter. A lease signed with a two-year-old local restaurant has more credit risk than the cap rate on a comparable national tenant deal would suggest.

Lease Term and Rent Bumps

The value of a NNN lease is partly a function of its remaining term. A 15-year lease is worth more than a 3-year lease because income is locked in for longer and rollover risk is deferred. Cap rates compress with longer remaining term and expand as expiration approaches.

Rent Bump Structures

Most NNN leases include scheduled rent increases that offset inflation and protect the income stream. Common structures:

Fixed annual percentage: 1.5–2% per year, compounding.
Stair-step bumps: 10% every 5 years. Simple and predictable.
CPI-linked: Tied to the Consumer Price Index. Protects purchasing power but creates variability.
Flat rent (no bumps): Found in older leases or weak credit situations. Real income erodes with inflation.

Year 5 Rent = Base Rent × (1 + Annual Bump%)⁵
= Example: $120,000 × (1.02)⁵ = $132,487

When modeling a NNN lease, project NOI for every year of the primary term using the actual bump schedule. Then decide how to value: discounted cash flow (more precise), or exit cap rate on Year 10 stabilized NOI (faster, common in practice).

Dark Risk: The Residual Exposure

“Dark risk” is what happens when the tenant goes dark — vacates the building. This can happen at lease expiration, during a bankruptcy proceeding, or if the tenant abandons the location. It is the primary long-term risk in single-tenant NNN investing.

Dark risk varies significantly by building type:

Building Type	Re-Tenanting Difficulty	Conversion Options
Generic retail box (10,000–25,000 SF)	Moderate	Multiple retail users, sometimes medical
Drive-through QSR (1,200–2,500 SF)	Difficult	Limited; must find another drive-through user
Pharmacy / big-box (10,000+ SF)	Very difficult	Re-tenanting takes years; conversion expensive
Flex / multi-use footprint	Easier	Broader range of users possible
Ground lease (tenant owns structure)	N/A – land only	Tenant owns and manages structure

Full Deal Walkthrough

Here is a representative single-tenant NNN acquisition to illustrate the full underwriting process.

Property Overview

Asset: 4,800 SF freestanding retail (regional auto parts chain)
Location: High-traffic arterial, secondary suburban market
Tenant: Publicly traded, non-investment-grade regional chain
Lease structure: Absolute NNN, no landlord obligations
Asking price: $2,100,000

Lease Economics

Base rent: $144,000/year ($30/SF)
Remaining primary term: 8 years (plus two 5-year options)
Rent bump: 10% every 5 years (stair-step)
Tenant expense responsibility: All taxes, insurance, maintenance, repairs

In-Place NOI and Cap Rate

Cap Rate = $144,000 ÷ $2,100,000
= = 6.86% in-place cap rate

Projected NOI Over Lease Term

Period	Annual Rent	Cumulative Income
Years 1–5 (current rent)	$144,000	$720,000
Years 6–8 (after Year 5 bump +10%)	$158,400	$475,200
Year 8 (end of primary term)	$158,400	—
Option period 1 (Years 9–13, +10%)	$174,240	$871,200

Year 8 Exit Analysis

Depends on Exit Cap Rate

Year 8 NOI

$158,400

Exit @ 6.5% cap

$2,437,000

Exit @ 7.5% cap

$2,112,000

Exit @ 8.5% cap

$1,863,000

At 8.5% exit cap (2 years remaining at expiration), the exit value is below the $2.1M purchase price despite 8 years of collected rent. Lease-term compression at exit is the core risk in NNN investing.

DSCR Analysis

Assuming 65% LTV at 7.25% on a 25-year amortization:

Loan amount: $1,365,000
Annual debt service: ~$115,200
DSCR: $144,000 ÷ $115,200 = 1.25x

1.25x DSCR clears most commercial lenders' 1.20–1.25x minimum. Not a lot of buffer — any rent interruption (tenant default, bankruptcy, dark event) immediately puts the deal into negative cash flow territory.

Option Periods and Renewal Analysis

NNN leases typically include renewal options at the tenant's election. These options are valuable to the tenant (they lock in below-market rent if the location performs well) and potentially risky to the landlord (the tenant only exercises if it is profitable for them, not necessarily at market rates).

When evaluating a deal with option periods remaining:

Check whether option rent is fixed, bumped from prior term, or reset to market.
Understand that the tenant will exercise if the rent is favorable to them — if market rents have grown, the tenant has a below-market option and will likely take it.
If market rents have declined relative to option rent, the tenant may not renew — and your income assumption falls apart.

Single-Tenant vs Multi-Tenant NNN

Most “NNN investment” discussion focuses on single-tenant freestanding properties. But NNN lease structures also appear in multi-tenant retail, flex, and mixed-use buildings.

Structure	Credit Risk	Dark Risk	Management Intensity	Cap Rate Range
Single-tenant, national credit	Low (bond-like)	High at expiration	Very low	4.5%–6.0%
Single-tenant, local credit	High (unrated)	High if purpose-built	Low (until default)	7.0%–10%
Multi-tenant NNN / CAM recovery	Diversified	Moderate (rolling vacancies)	Moderate	6.5%–8.5%

Multi-tenant NNN buildings — strip retail, flex parks — spread tenant credit risk across multiple occupants. No single tenant vacating destroys the entire income stream. The tradeoff is higher operational complexity, lease renewal management, and CAM reconciliation. For multi-tenant flex underwriting, see How to Analyze a Flex Space Investment.

Key Questions to Answer Before Buying a NNN Lease

What are the actual landlord obligations under the lease — not what the broker says?
What is the tenant's credit profile? Public rating or independent verification?
How many years remain on the primary term, and what happens at expiration?
What is the rent relative to market and relative to the tenant's sales?
What are the rent bumps, and are they fixed, CPI-linked, or flat?
What is the building worth as vacant real estate, independent of the lease?
What is the exit cap rate assumption at the end of the hold period, and how many years of lease term remain then?
How does DSCR hold up if the tenant misses rent for one or two months?

Ready to run the numbers on your own deal?

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Bottom Line

NNN leases are simpler to manage than almost any other commercial investment — but simpler to operate is not the same as lower risk. The risk has shifted from operational (maintenance, tenant management) to structural (lease expiration, tenant credit, re-leasing at end of term). That risk is less visible day-to-day, which is why it catches buyers who do not model it.

The keys are: verify the lease (not the label), stress-test the exit at a realistic cap rate with fewer years remaining, and make sure the DSCR gives you enough cushion for a short-term rent interruption. If all three hold up, NNN is genuinely one of the most passive commercial investment structures available.