Even as space hit the market in the third quarter of 2015 at 100 West Putnam Avenue in Greenwich and other office buildings, leasing activity kept up at a sufficient level to absorb it -- but only just barely. Harman International Industries will stay put at 400 Atlantic Street in Stamford, seven years after moving its headquarters here from Washington, D.C. The former Pitney Bowes world headquarters in Stamford, was among the large additions to available office space in Fairfield County during the third quarter of 2015, following Building and Land Technology's purchase of the building.