Co-owners Vulcan Real Estate and Group Health are putting the full-block Westlake/Terry complex in South Lake Union up for sale.

The 318,000-square-foot office-and-retail project, completed in 2007, is between Westlake Avenue North, Terry Avenue North, Thomas Street and Harrison Street. The office space is occupied by Group Health's headquarters and Microsoft.

Both owners said they intend to pour sale proceeds back into their core businesses: Health care for Group Health, more development for Vulcan.

The company has spearheaded South Lake Union's redevelopment, building office, research, residential and retail projects that total more than 4.6 million square feet. The Westlake/Terry sale is a first for Vulcan in the neighborhood.