Read changes in occupied commercial space, calculate net absorption, and understand why vacancy can rise even when absorption is positive.
Zero FluxUpdated 3 sources
On this page
What is net absorption?
Net absorption is the change in occupied real-estate space during a defined period. Subtract beginning occupied space from ending occupied space. A positive result means occupied space increased; a negative result means it decreased.
The NAIOP glossary measures it in square feet at building, submarket, or market level. The Commercial MLS-hosted dictionary also defines unit-based net absorption. Always state the unit and period, such as square feet during one quarter, rather than calling an unlabeled number a rate.
This guide covers commercial space and rental occupancy, not home-sales velocity. The residential absorption-rate guide explains sales relative to inventory. A sales percentage is not interchangeable with a net change in occupied square feet or rental units.
Calculate the occupied-space change
Net absorption = ending occupied space − beginning occupied space.
Occupied space equals total inventory minus vacant space in NAIOP's definition. Using consistent snapshots, the same calculation is ending inventory minus ending vacancy, less beginning inventory minus beginning vacancy. This is a space balance, not leased square footage minus all new construction.
Vacancy rate is different. It divides vacant space by inventory and expresses the result as a percentage. Absorption measures the change between dates; vacancy rate describes the share empty at a particular date.
Gross activity does not show the net result
NAIOP defines leasing activity as signed leases or committed square footage without regard to occupancy. Its gross-absorption entry describes space occupied without subtracting vacancies, while also listing leasing activity as a synonym. Because labels overlap, check what the report actually counts.
A hypothetical tenant moving between two 20,000-square-foot offices within one reporting market creates a lease transaction. If it occupies the new office and vacates the old one during the same period, with no other changes, market net absorption is zero. An unchanged renewal likewise does not add occupied area.
Use the provider's recognition rules
A signature, lease commencement, building delivery, and occupation can fall on different dates. NAIOP explains that signed commitments can appear in absorption later, when occupied. The Commercial MLS-hosted dictionary specifically excludes preleased space in buildings under construction to avoid double-counting tenants moving within a market. Do not assume every provider applies an identical cutoff.
Track additions, removals, and conversions
NAIOP's total-inventory definition excludes construction, adds delivered buildings, and removes demolished buildings or buildings changing use. Inhabitable renovations can remain included. NAI Global's explanation reinforces these inventory boundaries.
For consistent snapshots, inventory change equals additions less removals. A conversion out of office use leaves that office universe; any later residential delivery belongs to another one. Record whether removed space was occupied or vacant. Removing vacant space can lower vacancy without increasing occupied space. Check how the provider reconciles these events and any coverage revisions before attributing every change to tenant demand.
A hypothetical worked example
Every figure below is invented. Assume one commercial submarket, one property type, square-foot measurements, and one quarter. Coverage is unchanged, and no buildings are removed or converted. A 100,000-square-foot building enters completed inventory during the quarter.
Hypothetical quarterly inventory and occupancy balance
Measure
Beginning of quarter
End of quarter
Change
Total inventory
1,000,000 sq ft
1,100,000 sq ft
+100,000 sq ft
Occupied space
900,000 sq ft
940,000 sq ft
+40,000 sq ft
Vacant space
100,000 sq ft
160,000 sq ft
+60,000 sq ft
Vacancy rate
10.00%
14.55% (rounded)
+4.55 percentage points (rounded)
Net absorption is 940,000 − 900,000 = +40,000 square feet. The inventory-and-vacancy check gives the same result, (1,100,000 − 160,000) − (1,000,000 − 100,000) = +40,000.
One possible reconciliation is 30,000 square feet of additional occupation in existing buildings, 10,000 square feet vacated there, and 20,000 square feet occupied in the delivered building. These changes net to +40,000. The remaining 80,000 square feet in the new building are vacant.
Both absorption and vacancy rose because inventory expanded by 100,000 square feet while occupied area expanded by only 40,000. Positive absorption does not, by itself, prove a tightening market.
Read the report before the headline
Positive absorption means the measured universe gained occupied space; negative absorption means it lost occupied space. For example, a hypothetical decline from 900,000 to 870,000 square feet produces −30,000 square feet. Neither sign identifies the cause or guarantees a rent, income, or investment outcome.
Separate quarterly, year-to-date, and annual totals. Do not compare a single quarter with a full year. Note the report's as-of date and any later revisions.
2.
Match the reporting universe
Keep geography, property type, building class, minimum size, and provider consistent. Check owner-occupied buildings, subleases, and construction exclusions. NAIOP notes that providers' competitive inventories differ.
3.
Reconcile the balance
Read absorption beside beginning and ending occupied space, inventory, deliveries, removals, and vacancy. Ask for an explanation when coverage changes or adjusted figures prevent a straightforward reconciliation.
4.
Separate observation from forecast
Look across comparable periods and identify unusually large moves. Review rents, concessions, lease expirations, and future supply separately before using absorption in an underwriting assumption.
The real-estate underwriting guide explains how to preserve sources and approved assumptions. Absorption is one observed input, not a substitute for property-level analysis. This article is educational, not investment advice.
Frequently asked questions
QUICK ANSWERS
Net absorption is ending occupied space minus beginning occupied space for a defined period and reporting universe. Occupied space equals inventory minus vacant space. Keep the provider, geography, property type, units, and coverage consistent, and check any inventory adjustments or revisions.
Yes. If inventory grows faster than occupied space, vacant space can increase even with positive net absorption. In this guide's hypothetical example, occupied space increases by 40,000 square feet, but inventory grows by 100,000 square feet. Vacancy therefore rises from 10% to approximately 14.55%.
Not automatically. NAIOP's 2017 glossary distinguishes signed commitments from the later occupation that appears in absorption. The Commercial MLS-hosted dictionary excludes preleased space in buildings under construction. Check the specific report's recognition rules rather than treating every signed lease as immediate absorption.
No. Commercial net absorption is a net change in occupied area or units over time. A residential sales absorption percentage relates homes sold during a specified period to an inventory measure. These have different units, denominators, and purposes; they are not interchangeable indicators.