The team behind plans for a swanky private membership club in part of what's to become the new world headquarters that Aramark Corp. is building on the Schuylkill waterfront is boosting its footprint in the western Center City office property to make room for a separately managed coworking operation.

Fitler Club founder David Gutstadt said his group plans to lease an additional 32,000 square feet of the 2400 Market St. building for shared office space under its new Offsite at Fitler Club brand.

Offsite will offer designated offices, shared desks, and common areas for 300 users. The coworking space is in addition to the 75,000 square feet over parts of the building's lower three floors that the group is leasing for use by the Fitler Club itself.

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Gutstadt said the group decided to launch the shared workspace as a separate business in the expanded section so that parts of the existing club area that had been set aside for coworking offices could be designated for members' private, permanent business use instead.

Offsite is to be operated as a separate venture led by Gutstadt's investor group, and by developer PMC Property Group and private equtity firm Lubert-Adler Real Estate Funds, which own the 2400 Market St. building. The venture hopes to develop the business into a new coworking brand that can open in additional locations independently of the club, Gutstadt said.

Perks for Offsite coworking members are to include early dibs on Fitler Club memberships and access to some club amenities. Discounted coworking memberships will be available to club members.

Aramark has said it hopes to begin occupying 300,000 square feet of its new 450,000-square-foot waterfront headquarters building before the end of this year. Entercom Communications Corp. is also said to be relocating its headquarters there from Bala Cynwyd.

The Fitler Club is on track to open by the end of March 2019, with Offsite also opening in the spring. Gutstadt said the club already has sold more than 600 first-round memberships, which are expected to be capped initially at 1,000. A waiting list includes several thousand others who have applied, he said.