In Q3 2026, commercial market conditions across Upper Merion Township/King of Prussia (UMT/KOP) remained relatively stable. Industrial and retail markets continued to perform strongly, with vacancy rates declining to 2.6% and 2.3%, respectively. Medical property vacancy remained at 9.9%, while life sciences vacancy remained elevated at 22.6%, primarily due to changes at Discovery Labs and within the Renaissance Park corporate campus. Despite broader challenges facing the life sciences industry, GSK’s recently announced $800M biologics manufacturing expansion in UMT/KOP represents a significant investment in the region that reinforces the area’s prominence in the life sciences sector.

Consistent with the reporting methodology introduced in Q1 2026, King of Prussia District continues to report office and flex properties in Renaissance Park and Discovery Labs separately from the broader UMT/KOP market to best reflect underlying market conditions.

Across UMT/KOP office properties, excluding Renaissance Park and Discovery Labs, Class A vacancy declined slightly to 11.0%, while Class B vacancy decreased to 14.8%. Overall office vacancy fell to 11.3% across competitive leasable office buildings and 9.7% when including owner-occupied properties. Flex vacancy also declined to 4.0%, reflecting continued stability in this segment.

Within Renaissance Park and Discovery Labs, overall office vacancy stood at 32.3% across competitive leasable office buildings and 31.4% across all office inventory, while flex vacancy remained at 17.2%.

Qi Guo

Manager of Research & Data Analytics

King of Prussia District



Overall Commercial Properties

in UMT/KOP

Industrial: 2.6% vacancy | 6.5M total SF | 141 Properties

Retail: 2.3% vacancy | 6.1M total SF | 175 Properties

Medical: 9.9% vacancy | 529K total SF | 12 Properties

Life Science: 22.6% vacancy | 2.5M total SF | 22 Properties

Office/Flex Properties in UMT/KOP

Excluding Renaissance Park & Discovery Labs

Office/Flex Properties

In Renaissance Park & Discovery Labs

Featured Business

GSK’s $800M Biologics Manufacturing Expansion

On October 9, 2026, GSK announced plans to invest more than $800M in a new biologics manufacturing facility at its East Campus on River Road in UMT/KOP, marking one of the largest life sciences investments in the area's history. According to the Philadelphia Business Journal, the project is expected to create more than 300 jobs, with construction beginning in 2027 and full operations anticipated by 2030.

The new facility will bring together commercial manufacturing, research and development (R&D) manufacturing and advanced digital technologies. It will also include a pilot plant using artificial intelligence and automation to support drug development. The facility is expected to support up to 80% of GSK’s projected monoclonal antibody portfolio for cancer and respiratory diseases.

The investment builds on GSK’s long history in UMT/KOP. Its existing campus at 709 Swedeland Road occupies approximately 844K SF and supports an estimated 1,000 employees. Originally constructed in 1996, the manufacturing facility has undergone several upgrades to support changing production needs. In 2019, GSK invested $120M to integrate R&D and manufacturing operations, adding flexible production equipment and a new analytical laboratory. According to GSK’s 2024 Annual Report, digital scheduling improvements increased manufacturing capacity by 10%.

Other major investments have contributed to the area's life sciences manufacturing capabilities. In 2022, Center for Breakthrough Medicines, now part of SK pharmteco, secured $350M in equity financing to support cell and gene therapy manufacturing. That same year, Ecolab (formerly Purolite), completed a 74K SF manufacturing expansion. More recently, SK pharmteco announced a $100M global investment in viral vector manufacturing in 2026, including its King of Prussia operations.



Together, these investments, along with GSK’s latest expansion, reinforce UMT/KOP’s position as an established hub for advanced biopharmaceutical manufacturing and continued industry investment.

Highlight

King of Prussia Sees Continued Visitor Growth in Q3 2026

Visitation across UMT/KOP continued to grow in Q3 2026, reflecting the area's role as a regional destination for shopping, dining, employment and recreation. According to Placer.ai, UMT/KOP recorded approximately 11.9M non-resident visits from July through September, an increase of 4.4% compared to the same period last year.

Out-of-market visitation showed strong growth. The number of unique out-of-market visitors increased by approximately 9.4% year-over-year during Q3. In September alone, UMT/KOP attracted approximately 1.7M unique out-of-market visitors, reflecting continued interest from visitors traveling to the area.

Commuter activity showed mixed trends. While the number of unique inbound commuters declined by approximately 4.5% year-over-year, total inbound commuter visits increased slightly. Over the past 12 months, inbound commuter visits increased by 4.7% compared to the previous year, suggesting that commuters are making more frequent trips to the area.



Major commercial destinations continued to attract visitors from across the region. King of Prussia Mall recorded more than 100K additional visits in September compared to the same month last year. Approximately 65% of the mall's visitors lived more than 10 miles away, including nearly 24% who lived more than 30 miles away.



Together, these trends reinforce UMT/KOP’s position as a vibrant visitor destination and business center in Greater Philadelphia.

A longtime Germantown piano company opens its new King of Prussia HQ, hoping to grow a music scene in the suburbs

The King of Prussia building home to the Netflix House has sold for $60M

Not a complete listing. All sales and leasing info from CoStar.

King of Prussia District is a 501(c)3 that accelerates economic growth by making King of Prussia vibrant, attractive and prosperous. This mission and our core values –progressive, determined and fun – drive the work that we do every day across five programs. 

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DISCLAIMER

All information obtained using CoStar Analytics and field checked for accuracy by King of Prussia District. Vacancy rates are calculated using existing, non-owner occupied commercial buildings in Upper Merion Township only, over 10,000 SF, Class A, B, and C plus retail, industrial and flex. King of Prussia District uses "Direct % Vacant Available" in its vacancy reporting. All industrial and flex statistics are NNN.

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