At the moment, according to the recent Real Estate Update report from Fitch, the international rating agency based here, there are about 40 million sf of telecom space in the US or under construction. Many of those communications centers are being built in class B office buildings, industrial facilities and underutilized or abandoned malls. Space at these sites is typically provided with few improvement allowances and the tenant is often required to install heating, ventilation and air conditioning equipment, backup power as well as flooring, which can run up to $300 per sf to $400 per sf and more.

Fitch analyst Gregg Delany writes that telecom investors may face risks from new technologies that don't require land-based facilities, and that advances in software may mean that data networks are less "locationally sensitive."

Looking forward, Delany says there is room in the CMBS capital markets for conservatively underwritten loans secured by telecom centers, but notes that the high bond default rate of these companies and underscores the risks involved with their untested business models.