Share story has finalized long-rumored office leases for more than 546,000 square feet in three Seattle buildings, and inked yet another deal for 26,000 square feet in the newly renovated historic Supply Laundry Building, public records show.

Applications filed with the city within the past week show the technology giant is preparing to move into office space at Blanchard Plaza, Fifth & Bell and 635 Elliott Ave. W. The possibility of leases at the first two buildings has been circulating in the real-estate brokerage community since last fall, while talk of a lease with Seattle developer Martin Selig leaked earlier this year.

That’s a significant expansion of its already hefty footprint in Seattle: Amazon already leases or owns more than 5.2 million square feet of office space, including about 2 million square feetunder construction. The tech juggernaut also has approvals to build another 2.2 million square feet on its future Denny Triangle campus and earlier this year bought nearly an entire city block from Clise Properties.

At Blanchard Plaza, Amazon has signed an 11-year lease for more than 255,000 square feet, public records show. Permits for tenant improvements show Amazon will occupy most of the 15-story building, which is owned by San Francisco-based Shorenstein Properties. The improvements include a $2.5 million remodeling of the building’s second floor for conference rooms and offices, records show.

At Fifth & Bell, which is owned by Houston-based Hines, Amazon has received a permit for improvements on the first, second and third floors of the six-story building. The space adds up to just over 100,000 square feet.

And at 635 Elliott Avenue West, Amazon has agreed to a five-year lease for the four-story building with expansive views of Elliott Bay. Amazon applied for a permit last week for improvements to all four floors.

In addition, has signed a 10-year lease with developer Vulcan for the office portion of the historic Supply Laundry Building and for parking rights in the parking garage beneath the Stack House Apartments, public records show. The building is at the corner of Republican Street and Yale Avenue North.

Vulcan, which redeveloped the century-old brick structure, confirmed the 26,000 square-foot office space has been leased but refused to comment on the tenant. Vulcan also developed the 278 apartments on the block.

Amazon officials didn’t respond to a request for comment on Monday.

Sanjay Bhatt: 206-464-3103 or On Twitter @sbhatt