SAM officials will decide this week whether to endorse the plan that could triple its space. The plan also calls for replacing the eight-story, 270,000-sf Museum Plaza building, which is sandwiched between first and second avenues on Union Street Downtown. It sits about half a block from the existing Washington Mutual Tower building. The 75-year-old Plaza building is fairly empty, as Nordstrom and Seattle's Best Coffee have moved their administrative operations out of the building.

Washington Mutual, one of Downtown's largest tenants, has expanded its operations throughout the country in the last few years. Despite a Seattle vacancy rate that keeps increasing (from 13.82% in January to 15.53% mid-year), the banks says it needs to add more space for its Puget Sound headquarters and would like to consolidate its facilities.

The bank had contemplated constructing a tower in the Denny Regrade area, but opted to try and consolidate its 4,000 employees near its existing 55-story tower in the financial district on Third Avenue. WaMu employees now work in about a dozen area facilities in addition to the namesake tower.