OpenAI is expanding its footprint in downtown Bellevue by leasing additional office space, according to a February 3 report from commercial real estate data firm CoStar.
The artificial intelligence company first opened offices in Bellevue in 2024 near Microsoft, its longtime partner. The collaboration began in 2019 with a $1 billion investment from Microsoft, followed by an additional $10 billion announced later, giving Microsoft a 49 percent ownership stake in OpenAI. The two companies have since worked together to integrate OpenAI technology into a range of Microsoft products.
In 2025, OpenAI expanded again by leasing two floors at City Center Plaza in downtown Bellevue at 555 110th Avenue Northeast. The space had previously been occupied by Microsoft, which vacated the building in 2024 when its lease expired, leaving more than 500,000 square feet available.
OpenAI’s Bellevue offices now total approximately 272,000 square feet. An industry source cited by CoStar said the space could accommodate more than 1,800 employees, though not all areas will be used for office workstations. Permit filings from last year show plans for amenities, including a cafeteria and a game room.
Much of the space OpenAI has taken over in Bellevue was formerly leased by Microsoft. In recent years, Microsoft has vacated more than 2 million square feet of office space in the city as it consolidated employees at its Redmond campus.
