The deal is a welcome one for the Tyson's submarket, which has seen sizable move-outs by technology, financial and professional services tenants over the last year, according to Jones Lang LaSalle's research director, Scott Homa, who did not have direct knowledge of the lease or comment on it specifically.

All told, there was one million square feet of negative net absorption in Tysons Corner in 2009, according to JLL statistics--the largest contraction of any submarket in the metro DC region, Homa tells GlobeSt.com. The resulting vacancy surpassed the 20% mark for the first time since 2004. A rise in sublease space also contributed to the decline, with average sublets quoting rates nearly 10% below direct space.

For better or worse, Tysons Corner has a tenant base that embodies the characteristics of the broader national economy, Homa says. For the past year its real estate activity has essentially reflected fundamentals that are similar to the rest of the nation, bypassing many of the stabilizing forces of the metro DC area. "Aside from a handful of intelligence agencies, the federal government accounts for a relatively small portion of the overall tenant base in Tysons Corner," he says. As a result, "the counter-cyclical growth of many federal agencies during the past 12 months has benefited other submarkets, most notably Crystal City and the Rosslyn-Ballston Corridor, while sidestepping Tysons Corner."