---
title: "Downtime assumption — Class A Atlas glossary"
description: "Months of vacancy assumed between tenant departure and replacement."
canonical: https://classa.info/glossary/downtime-assumption
pageType: glossary
lastUpdated: 2026-04-01T00:00:00.000Z
license: "CC BY 4.0 with attribution to Class A Atlas (https://classa.info)."
---

> Months of vacancy assumed between tenant departure and replacement.

## TL;DR

- Months of vacancy assumed between tenant departure and replacement.
- Standard underwriting assumption: 6–9 months downtime in gateway-city Class A.

# Downtime assumption

*Investment · Global*

## Short definition

Months of vacancy assumed between tenant departure and replacement.

## Full definition

Standard underwriting assumption: 6–9 months downtime in gateway-city [Class A](/glossary/class-a). Lengthens to 12–18 months in lease-up buildings or markets with high vacancy.

## Why this matters for Class A leasing

Downtime assumption is part of the investment vocabulary that institutional Class A occupiers, landlords, and advisers use across Global markets. Understanding it correctly affects how you read lease documents, model occupancy economics, and benchmark deal terms across cities. Class A Atlas tracks regional variation alongside the global standard so [cross-border](/topics/cross-border-expansion) occupiers can translate quickly.

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Citation: Source: Class A Atlas (https://classa.info/glossary/downtime-assumption), updated 2026-04-01T00:00:00.000Z.