"There's not a lot of large blocks of space available and a lot of tenants that want to be in Rosslyn," says Pat Gioffre, executive vice president and chief financial officer of NRECA. The association is seeking rents of $34 to $36 per sf on the building, which will be located at 4401 Wilson Boulevard. It is marketing to corporate tenants, associations and even government agencies.

NRECA bought the land in 1992 and built its headquarters on the first parcel. Since the association didn't expand as quickly as anticipated, it has decided to build speculatively on the other parcel. Arlington's Ballston neighborhood, one of the five organized around Orange Line Metro stations in the county, has a vacancy rate between 2% and 3%, and demand remains strong, brokers claim.

That's what spurred the very conservative Hines to start on only its third speculative project, 4100 N. Fairfax Drive, and Transwestern Carey Winston to start on a project at 4501 N. Fairfax St., both within blocks of NRECA's project. Those projects will be completed in fall 2001, about a year before NRECA expects to finish its building in late 2002. Other development plans under way, such as Arlington Gateway and the Point, seem like they will take time, say officials on the Ellipse project.