Modeling Percentage Rent Escalators: A Step-by-Step Underwriting Walk-Through

TL;DR

Percentage rent (also called "overage rent") is a contractual provision in many retail leases where the tenant pays the landlord a percentage of gross sales above a defined threshold ("breakpoint"). The structural math is: percentage rent = (gross sales − breakpoint) × rate.

Most OMs treat percentage rent as either ignored (assume zero) or guaranteed (assume always paid at projected sales). Both approaches are wrong. The right framework treats percentage rent as a probability-weighted upside that depends on tenant sales trajectory, breakpoint level relative to current sales, and the percentage rate.

How Percentage Rent Works

Standard structure:

"Tenant shall pay Landlord percentage rent equal to 6% of Gross Sales in excess of $5,000,000 per Lease Year."

In this example:

• Breakpoint: $5,000,000 in annual gross sales
• Rate: 6%
• Percentage rent if sales = $6,000,000: ($6,000,000 - $5,000,000) × 6% = $60,000

The lease will define:

• Gross Sales: typically all sales at the location, with specific exclusions (employee discounts, returns, sales taxes, gift card sales, etc.)
• Breakpoint: usually a fixed dollar amount, sometimes indexed to base rent
• Percentage Rate: typically 4-10% depending on retail category

The "Natural Breakpoint" Convention

In many retail leases, the breakpoint is set at the level where base rent ÷ percentage rate = breakpoint. This is the "natural breakpoint" — the sales level at which 6% of sales would equal annual base rent.

Example:

• Annual base rent: $300,000
• Percentage rate: 6%
• Natural breakpoint: $300,000 / 0.06 = $5,000,000

The economic logic: a tenant would be indifferent between paying base rent or paying percentage-rent-only at this sales level. Above the breakpoint, the percentage rent yields more than base rent — landlord captures the upside.

In a "natural breakpoint" structure, the tenant's total rent for the year is:

• If sales ≤ breakpoint: tenant pays base rent only
• If sales > breakpoint: tenant pays base rent + percentage rent on overage

Two Common Variations

Fixed (Unnatural) Breakpoint

Some leases set the breakpoint at a level different from natural — either above (tenant-favorable) or below (landlord-favorable). For example:

• Natural breakpoint: $5,000,000
• Lease specifies: $4,000,000 (landlord-favorable)
• Lease specifies: $7,000,000 (tenant-favorable)

For a landlord-favorable breakpoint, percentage rent kicks in earlier — meaningful upside if the tenant performs well.

CPI-Indexed Breakpoint

Some leases reset the breakpoint annually based on CPI:

"Breakpoint shall be increased by the CPI growth from the prior year, capped at 4% per year."

This protects the landlord from inflation eroding the real value of the breakpoint over the lease term.

Underwriting Framework

The underwriting question for percentage rent is: how much value should it contribute to the deal valuation? Three approaches:

Approach 1: Ignore It (Conservative)

Don't include percentage rent in NOI. Treat it as upside that doesn't affect base case underwriting.

When this makes sense:

• Current sales are below breakpoint (no current percentage rent)
• Tenant credit is weak (sales trajectory uncertain)
• You're underwriting at a tight cap rate where any optionality is a bonus

Approach 2: Probability-Weight It (Most Realistic)

Estimate the probability of percentage rent being paid in each year of the underwriting horizon, multiply by expected percentage rent, include in NOI.

When this makes sense:

• You have visibility to tenant sales (or industry benchmarks for the brand)
• You're building an institutional model and want defensible numbers
• The percentage rent component is material to the deal

Approach 3: Include It at Pro-Forma Sales (Aggressive)

Project tenant sales above the breakpoint, calculate percentage rent at that level, include in NOI.

When this makes sense:

• Rarely. This approach overstates value because percentage rent is contingent and shouldn't be capitalized at base-NOI rates.

Worked Example

Deal facts:

• Tenant: chain restaurant, 4,500 sq ft freestanding building
• Base rent: $315,000/year ($70/sf NNN)
• Lease has percentage rent: 6% of gross sales over $5,250,000 breakpoint (natural breakpoint: $315,000 / 0.06 = $5,250,000)
• Most recent reported tenant sales: $6,800,000
• Cap rate: 6.0% (asking)

Step 1: Calculate Current Percentage Rent

Sales overage: $6,800,000 - $5,250,000 = $1,550,000

Percentage rent: $1,550,000 × 6% = $93,000

So total current rent is $315,000 + $93,000 = $408,000.

Step 2: Three NOI Scenarios

Scenario A — Base rent only:

• NOI: $315,000
• Value at 6.0% cap: $5,250,000

Scenario B — Base + current percentage rent:

• NOI: $408,000
• Value at 6.0% cap: $6,800,000

Scenario C — Base + percentage rent at projected sales (assume 3% sales growth):

• Year 1 sales: $7,000,000 → percentage rent: $105,000
• NOI: $420,000
• Value at 6.0% cap: $7,000,000

Step 3: Probability-Weight

Realistic underwriting weights the scenarios:

• Probability tenant maintains sales above breakpoint over 5-year hold: 70%
• Probability sales decline materially (e.g., to $5,500,000): 20%
• Probability of significant sales weakness (below breakpoint): 10%

Probability-weighted year-1 NOI:

• $408,000 × 70% = $285,600
• $330,000 × 20% = $66,000 ($5,500,000 - $5,250,000 = $250,000 × 6% = $15,000 overage + $315,000 base = $330,000)
• $315,000 × 10% = $31,500

Total: $383,100

Probability-weighted value at 6.0% cap: $6,385,000

Step 4: Cap Rate Adjustment

Some underwriters apply a different cap rate to the percentage-rent component vs the base rent component, reflecting the higher uncertainty of overage rent. For example:

• Base rent: 6.0% cap → $5,250,000 value
• Percentage rent: 7.0% cap → ($93,000 / 0.07) = $1,328,571 value
• Total: ~$6,580,000

This is methodologically cleaner than blending into a single cap rate but produces similar results.

What to Verify in the Lease

Three things to nail down before relying on percentage rent in your model:

1. The Definition of "Gross Sales"

Gross sales definitions vary widely. Common exclusions:

• Sales tax
• Returns and allowances
• Employee discount sales
• Gift card sales (until redeemed)
• Online or third-party delivery sales (sometimes excluded)
• Catering sales (sometimes excluded)

A lease that excludes online/delivery sales materially affects your underwriting if the brand has growing off-premises revenue. For example, a Chipotle deal with delivery and digital sales excluded from "Gross Sales" understates the percentage rent base by 30-50%.

2. Tenant Reporting Obligations

How does the landlord verify gross sales? Most leases require:

• Annual sales certifications (signed by tenant officer)
• Right to audit (at landlord's expense, with cure period)
• Quarterly or monthly reports for some structures

If the lease has weak audit rights, the landlord has limited ability to verify overage rent calculations. This is a structural concern — particularly if the tenant has incentive to under-report.

3. Co-Tenancy and Reduction Triggers

Some retail leases include "reduction in percentage rent" provisions if certain conditions are met (anchor tenant vacates, occupancy drops below threshold, etc.). These are typically tied to the same triggers as base-rent abatement co-tenancy provisions.

If percentage rent is a meaningful component of the underwriting, verify whether co-tenancy reductions apply.

Common Underwriting Mistakes

Mistake 1: Modeling at Pro-Forma Sales Without Probability Weighting

Underwriting includes percentage rent at "tenant projections" or "industry growth rates" without probability-weighting against scenarios where sales decline or stagnate. This consistently overstates value.

Mistake 2: Capitalizing Percentage Rent at the Base Cap Rate

Percentage rent has higher uncertainty than base rent — it should be capitalized at a wider cap rate (typically 100-200 bps wider), or probability-weighted as in the example above.

Mistake 3: Ignoring Percentage Rent When It's Material

The opposite mistake: ignoring percentage rent altogether when it represents 20%+ of total tenant rent. This leaves real value on the table for the seller. For high-performing locations, accurate percentage rent modeling is worth meaningful dollars in the value calculation.

Mistake 4: Not Verifying the Definition of Gross Sales

A "Gross Sales" definition that excludes growing revenue streams (online, delivery, catering) creates a hidden underwriting issue — the percentage rent base may be smaller than the headline tenant sales suggest.

Practical Workflow

For any deal with percentage rent:

1. Read the percentage rent clause carefully — note the breakpoint, rate, and Gross Sales definition
2. Pull current tenant sales if available — many sellers will share with NDA for high-performing locations
3. Calculate current percentage rent to establish the actual current cash flow
4. Build three scenarios (no overage, current overage, growth case) and probability-weight
5. Choose between blended cap rate or split cap rate approach
6. Document the methodology in your IC memo so you can defend the value during review

Closing

Percentage rent is real value when it's already being paid and the tenant has a stable sales trajectory. It's also the source of meaningful underwriting variance because reasonable people can model it differently.

The discipline is to be explicit about your assumptions and to avoid extreme positions (ignoring it entirely or capitalizing it at base cap rates). Probability-weighted scenarios at modestly wider cap rates produce defensible numbers that survive IC scrutiny.