A super-regional owner, manager and developer of office and industrial properties, the Malvern, PA-based REIT has a portfolio of 660 properties with 49 million sf and a total market capitalization of $4.1 billion. Suburban office buildings account for 51% of the company's aggregate base rental revenue, 26% comes from R&D/flex properties and the balance from industrial distribution facilities.

Fitch's ratings reflect the diversity of Liberty's holdings, its modest merchant building program and it preference for wholly owned properties rather than joint ventures. Other factors include its nearly 30 years of operations, strong senior and local management and stable capital structure.

Issues of concern include the cash flow variability of office properties and leasing risks connected with its $391-million development pipeline. Although Liberty's holdings are judged B/B+ overall, their location in suburban areas with low barriers to entry and in secondary markets means they may be subjected to supply pressure. Institutional investors may not find such a portfolio attractive in a downturn, according to Fitch.