Dweck Properties has put Stafford Place I and II, at 4201 and 4121 Wilson Blvd., in Ballston up for sale after the landlord still doesn’t know if the National Science Foundation plans to renew its leases in both buildings, The Washington Post reported.

Dweck Properties sent sales materials to potential buyers in early June through Transwestern, advertising the 768,163-square-foot buildings as 100 percent leased in large part because the National Science Foundation occupies 86 percent of them.