Large-block availability peaked in late 2024 and is now beginning to tighten, primarily driven by the expansion of AI companies. In response, landlords are proactively reshaping stacking plans to preserve flexibility and capture demand. As large-block options become scarcer, developers may become increasingly incentivized to break ground for the first time since 2023.
Although most large-block leasing has been concentrated in the CBD and Mission Bay, San Francisco’s non-core submarkets are now also showing meaningful declines in availability. Citywide, the number of large blocks has fallen to its lowest level since Q1 2023.
The larger the tenant requirement, the fewer the viable options. Across San Francisco’s 600+ office buildings, only 13.0% can accommodate tenants seeking more than 50K sf, and just 5.4% can support requirements above 100K sf. Availability is stronger among Class A assets, where 31.9% can accommodate 50K+ sf tenants, though that share falls sharply to 13.2% for 100K+ sf requirements.
