Share story, already one of Seattle’s largest employers, now is also one of its biggest property-owners.

The online retailer closed Friday on the purchase of its 11-building South Lake Union headquarters campus, previously leased from Paul Allen’s Vulcan Real Estate.

Amazon paid Vulcan $1.154 billion, according to public records. That’s slightly less than the $1.16 billion price tag the companies put on the deal when they announced it in early October.

Research firm Real Capital Analytics said at that time that the deal was in line to be the country’s largest single-asset commercial real-estate transaction of the year. It’s also King County’s biggest sale since 2007, when the 28-building Equity Office Properties portfolio changed hands for $2.76 billion.

The deal became final just one day after ever-expanding Amazon closed on three Denny Triangle blocks, paying Seattle’s Clise Properties $207.5 million.

Amazon plans a high-rise office complex there, and it’s moving at typical speed — its general contractor already has put up a construction fence around the first block slated for development.

In South Lake Union, Amazon is getting nine new and two renovated historic buildings along Boren and Terry avenues. Together, they contain 1.7 million square feet of office space and 100,000 square feet of retail.

The price Amazon paid breaks down to $644 per square foot, by some measures a Seattle market record.

Vulcan started building the complex in early 2008 after signing Amazon to long-term leases.

Amazon moved into the first building in spring 2010, and the last building was completed this fall.

Vulcan said in a statement Friday that it intends to plow proceeds of the sale back into South Lake Union.

The neighborhood “will continue to be at the heart of our redevelopment efforts,” Vice President Ada Healey said.

The company, owned by Microsoft co-founder Allen, has developed nearly 30 acres in the once-neglected area over the past decade and plans to develop 30 more.

Information from The Seattle Times archives is included in this report.

Eric Pryne: or 206-464-2231