Route 128 and Interstate 495 have been witness to an unprecedented boom in office space and lease rates, most of it from high-tech companies. At one time, $40 per sf was thought to be the barrier rate on 128 but since then rates have shot past that up to $50 per sf.

"We're going to see a rolling technology correction," says Stephen Coyle, director of market research at Boston–based Property & Portfolio Research in an interview with Globest.com. "The artificial exuberance will pull lease rates down somewhat. "

With financing running dry, a number of start-ups have been forced to dump their office space on the market. At Watertown Arsenal, a trio of firms put empty offices up for rent. CMGI Inc. has been scaling back on its network of Internet companies. CA-based Cisco Systems, which has plans for nearly two million sf of office space along 495, recently took a big hit in the stock market. New Jersey-based Lucent Technologies' plans to build a large office complex on 495 have recently become less clear.