Same-Store NOI: Definition, Formula, and REIT Growth Analysis

Same-store net operating income (same-store NOI) compares Net Operating Income from a defined set of properties that were owned and operating during both comparison periods.

The purpose is to reduce the effect of acquisitions, dispositions, new developments, and other portfolio changes when measuring organic property-level growth.

A common growth calculation is:

Same-store NOI growth = (Current-period same-store NOI ÷ Prior-period same-store NOI) - 1

Example

Suppose a REIT's same-store portfolio generated:

• $420 million of NOI this year; and
• $400 million last year.

Then:

Same-store NOI growth = ($420m ÷ $400m) - 1 = 5%

If total-company NOI grew 12% because the REIT also acquired several properties, the 5% same-store result gives a cleaner view of growth from the existing comparison portfolio.

The same-store pool matters

There is no universal same-store portfolio definition. An issuer may require a property to have been owned, stabilized, and operating for a specified period. Redevelopments, casualty events, major renovations, held-for-sale assets, or properties under lease-up can be excluded.

A REIT can therefore report positive same-store NOI growth while total NOI falls, or the reverse.

What drives same-store NOI

Common drivers include:

• contractual rent increases;
• new and renewal lease spreads;
• Occupancy Rate;
• tenant defaults or bad debt;
• property taxes and insurance;
• repairs, utilities, and payroll; and
• concessions or other property-level revenue changes.

The mix differs by property type. Apartment, industrial, office, retail, self-storage, hotel, and healthcare REITs can have very different lease structures and expense sensitivity.

Same-store NOI is not company earnings growth

Same-store NOI excludes financing costs, corporate overhead, depreciation, many capital expenditures, and properties outside the same-store pool. It is therefore not equivalent to FFO growth, AFFO growth, earnings growth, or cash-flow growth.

It is best read as an organic property-operating metric.

Comparison rule

Before comparing two REITs, verify:

• the qualification period for a same-store property;
• stabilized versus non-stabilized treatment;
• acquisition and disposition exclusions;
• redevelopment rules;
• cash versus GAAP rent treatment; and
• whether NOI itself is defined consistently.

A same-store growth percentage without the pool definition is incomplete.

Sources

• Independence Realty Trust 2025 Form 10-K
• Nareit discussion of same-store NOI

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