BNY Mellon Building, 1735 Market St., Philadelphia, PA (Jeffrey M. Vinocur photo for Wikipedia, used under Creative Commons 2.5 license)

PHILADELPHIA, PA—Lease rates for class A office space in Philadelphia's central business district reached an all-time high of $33 per square foot per year in 2018, fueled largely by investors seeking to recoup the money they invested in fancier amenities, according to CBRE's  fourth quarter MarketView report on the office market.

Office sales volumes in the fourth quarter were nearly double the third quarter, with trophy buildings like Eight Tower Bridge in Conshohocken selling for $313 per square foot, and 1735 Market Street in the CBD going on sale, CBRE says.

Liberty Property Trust continues to unload its office portfolio, with several prominent sales in Malvern, west of the city, as part of a publicly announced rotation out of the office sector in favor of increased investment in industrial properties.

Tenant improvement allowances continued a rising trend since 2010, CBRE says, reaching $4.72 per square foot per year.

Despite the rising rents, vacancy rates remained stable at about 14.5%, CBRE's research says, although class A vacancy rates declined from the third quarter. Occupancy gains from a new headquarters opened for food and venue services firm Aramark were offset by some large office relocation and downsizing activities, such as software company Optymyze's move from Chester, PA into 1700 Market Street in Center City.

CBRE says the pipeline of new office construction is mostly empty, except for build-to-suit properties that won't contribute much to availability. Like Brandywine Realty Trust, which is renovating its office property at 500 N. Gulph Road in King of Prussia, landlords are likely to continue renovating existing assets to keep them competitive, CBRE says.