Fannie Mae is making moves as it prepares to relocate its iconic Wisconsin Avenue headquarters to a new building in downtown Washington by consolidating its three properties in Northern Virginia into one central hub. The GSE is looking to sell three office buildings in Reston and Herndon, VA, where it leases about 1.5 million square feet of space. Fannie recently signed on to be the anchor tenant at Reston Gateway, occupying 850,000 square feet. The building is currently under construction and Fannie is set to move into the mixed-use property in 2022. With about three years left before the move into the new Reston office, observers said the GSE could execute a sale-leaseback...