US office leasing activity rose 5% year-over-year, with Boston reporting the highest growth in the metric, according to year-end data from CoStar, a leading global provider of online real estate marketplaces, information and analytics in the property markets.
Office tenants signed for an estimated 410 million square feet of space in 2025 – an increase from 2024, when leasing volume fell to its lowest level in 15 years (excluding 2020).
Additionally, the year closed with three consecutive quarters of volume exceeding 100 million square feet – a first since the opening three quarters of 2022.
These figures reflect new office leases executed during 2025, including an estimate of those executed during the year but not yet recorded by CoStar research. Renewal leases are not included.
“Despite the rebound in 2025, leasing activity has yet to return to the level seen in the late 2010s,” said Phil Mobley, National Director of Office Analytics at CoStar Group. “While transaction activity is near its all-time high, with approximately 30,000 lease deals last year, the average lease size was roughly 3,500 square feet – more than 15% smaller than the five-year pre-pandemic average.”
At the market level, Boston saw the largest year-over-year growth in leasing activity (+52%), which lifted annual volume to its pre-pandemic five-year average. San Jose and San Francisco followed with a 40% gain in the metric, likely driven largely by demand from AI firms.
Markets with declines in leasing activity include Seattle, Atlanta, Houston and Philadelphia.
