Glossary

Availability Rate

Also known as: available space rate

The percentage of total inventory that is being actively marketed for lease or sale as of the survey date, including space that is currently occupied but will become available within a defined future window (typically 6-12 months) — distinct from and generally higher than the vacancy rate, which counts only physically empty space.

Availability rate is the broader and, for forward-looking underwriting, often more decision-relevant metric than vacancy rate because it captures known future competitive supply — space where a tenant has given lease-expiration or termination notice, or has listed for sublease while still in occupancy — that vacancy statistics miss entirely. The gap between availability and vacancy (sometimes called the 'shadow gap') widens when tenants pre-market space well ahead of expiration, which is common in soft markets where landlords and tenants alike want early visibility into re-leasing risk. Data providers such as CoStar and JLL report both metrics, and analysts comparing markets or historical periods must confirm which one a stated figure references, since a market can show stable vacancy while availability is climbing sharply — an early warning sign of softening that a vacancy-only view would miss.