Anthropic signs 13-year lease for entire 300 Howard Street tower, expanding downtown San Francisco footprint

A rare single-tenant deal signals continued AI-driven demand for premium San Francisco office space

Anthropic has signed a long-term lease to occupy an entire office tower in downtown San Francisco, committing to all space at 300 Howard St., a high-rise near the Salesforce Park corridor. The agreement positions the artificial intelligence company to consolidate and expand its local operations at a time when many large employers continue to shrink their office footprints.

The lease covers roughly 420,000 to 480,000 square feet across the full building, which has also been known in the market by its former address branding as 199 Fremont. The term is a 13-year commitment, with occupancy expected to begin in 2027. The structure had previously housed major technology tenants, including Fitbit and StubHub, before it went largely vacant in the post-pandemic office downturn.

The building has been renovated and repositioned by its ownership group, and the transaction stands out for its scale: a full-building, single-tenant commitment is uncommon in a market still working through elevated vacancy and weak leasing volume across older downtown inventory.

How the lease fits Anthropic’s existing presence

Anthropic has already built a significant footprint in the South of Market/downtown core. In 2023, the company took over a large block of space at 500 Howard St. through a sublease after Slack reduced its in-office needs. In 2025, Anthropic also expanded by leasing additional space at 505 Howard St., in the Foundry Square complex across the street. The new 300 Howard St. lease creates a path to bring more of its teams together within a single building over the longer term.

• Location: 300 Howard St., downtown/South of Market area near Salesforce Park

• Scale: Full-building lease, roughly 420,000–480,000 square feet

• Term: 13 years

• Timing: Occupancy expected to start in 2027

Company growth and the downtown office market context

Founded in 2021 by former OpenAI leaders, Anthropic has expanded rapidly, reporting a workforce of roughly 2,500 employees globally, including more than 1,300 in the Bay Area. The company develops AI models and products centered on its Claude assistant, and it has attracted significant investment as competition accelerates in the generative AI sector.

The deal also lands amid a broader pattern in San Francisco: while many legacy tech tenants have reduced space since 2020, AI firms and adjacent investors have been among the most active in pursuing large, high-quality offices. Recent market activity has included additional sizable negotiations and leases by AI companies in neighborhoods near the downtown core.

Anthropic’s full-building lease at 300 Howard St. ranks among the largest downtown office commitments since the pandemic-era reset.

For San Francisco’s commercial real estate market, the transaction provides a high-profile example of demand concentrating in newer, amenity-rich properties and reinforces the city’s role as a major center for AI employers even as overall office recovery remains uneven.