U.
S. office leasing activity increased by 5% year-over-year in 2025, with Boston registering the highest growth among major markets, according to new data from CoStar, a global provider of real estate information and analytics.
The latest figures reveal that office tenants secured an estimated 410 million square feet of space in 2025. This marks a notable increase from 2024, when leasing volume reached its lowest point in 15 years, excluding 2020. Furthermore, the year concluded with three consecutive quarters where volume surpassed 100 million square feet, a pattern not observed since the first three quarters of 2022. These statistics encompass new office leases executed during 2025, including an estimate of those completed but not yet recorded by CoStar research, and do not include renewal leases.
Phil Mobley, national director of office analytics at CoStar Group, commented on the findings, stating, “Despite the rebound in 2025, leasing activity has yet to return to the level seen in the late 2010s.” He added that while transaction activity is close to its all-time high, with approximately 30,000 lease deals last year, the average lease size was roughly 3,500 square feet, which is more than 15% smaller than the five-year pre-pandemic average.
At the market level, Boston experienced the most significant year-over-year growth in leasing activity, soaring by 52%, which brought its annual volume back to its pre-pandemic five-year average. San Jose and San Francisco followed, both showing a 40% gain in leasing volume, a trend attributed largely to demand from artificial intelligence (AI) firms. Conversely, markets such as Seattle, Atlanta, Houston, and Philadelphia saw declines in leasing activity. CoStar Group, founded in 1986 and headquartered in Arlington, Virginia, provides commercial real estate information, analytics, online marketplaces, and 3D digital twin technology globally. The company’s platforms, which include CoStar, LoopNet, Apartments.com, Homes.com, Matterport, STR, Ten-X, and OnTheMarket, collectively attracted over 141 million average monthly unique visitors in the third quarter of 2025.
