Another prominent office building in Philadelphia has sprung a major leak in occupancy.

Comcast made a seven-floor block of office space at Three Logan Square available for sublease in January, according to JLL Philadelphia research data confirmed by Bisnow. JLL research estimated the size of the newly vacated block to be nearly 160K SF, but the footprint on offer totals 138K SF, Comcast spokesperson John Demming said.

"The space is available as we are moving employees from Three Logan to the Comcast Technology Center," Demming wrote in an emailed statement. "As a global media and technology company, our culture thrives on in-person interaction and collaboration and so bringing our employees from Three Logan to our own space at the Comcast Technology Center helps achieve that."

With an official address of 1717 Arch St., the 53-story, 1M SF Three Logan Square sits kitty-corner from the Comcast Technology Center, which was completed in 2018. Brandywine Realty Trust has owned the rosy granite skyscraper, once known as the Bell Atlantic Tower, since purchasing it from a Blackstone affiliate in 2010. Representatives from Brandywine did not respond to requests for comment.

In 2017, Comcast signed a new lease at Three Logan for 300K SF, and it will continue to occupy seven floors at the building in addition to what it has vacated and put up for sublease, a Comcast representative said. Those remaining seven floors represent the entirety of office space Comcast now occupies in Center City outside of its two skyscrapers. Its lease at the building runs until 2029.

The addition of another major block of space adds to what had already been a record level of sublease availability in Philly's office market, JLL reports. At the end of 2022, 4.1% of the office inventory in the city's central business district was available for sublease. With Comcast's move, that percentage pushed higher, and the total sublease availability in the Philly CBD cracked 1M SF for the first time.

Several Philly office buildings also have large blocks of direct availability, but the lack of prospects for filling those spaces have tanked those buildings' values, putting the debt their owners carry in a precarious position.