Supply
Vacancy began to stabilize during the second quarter as Boston’s life sciences market recorded one of the smallest quarterly increases in recent history, ticking up 70 basis points (bps) to 34.9%. Despite the climb, vacancy in 11 of 19 submarkets remained stable or declined quarter-over-quarter (QOQ). After reaching a new record-high during the first quarter with 3.7 million square feet (msf) on the market, sublease availability declined modestly by 1.9% to 3.6 msf. Decreases in sublease space were widespread with all clusters but the 495 Belt recording annual declines. Move outs continued to outpace move ins as the market posted quarterly net occupancy losses of 337,000 square feet (sf). However, three of the five geographic clusters— 495 Belt, CBD, and Urban Ring —posted positive net absorption during the second quarter.
The pipeline remained unchanged with no new deliveries occurring in the second quarter and has contracted to its lowest level in the current market cycle as just four properties totaling 2.2 msf remain under construction. All four projects are set to deliver before year-end 2026, with all but one being build-to-suit projects, which will mitigate the impact on market fundamentals. However, the only speculative project in the pipeline, 421 Park Drive, remains fully available for lease.
Demand
Following a strong first quarter when new leasing activity surpassed the 1.0-msf mark for the first time in three years, second quarter demand aligned with recent averages at 367,000 sf, boosting year-to-date (YTD) totals to 1.7 msf. The bulk of quarterly demand was concentrated in the 495 Belt and Urban Ring, both of which surpassed the 100,000-sf mark. AdvanCell’s 128,000-sf lease for a new U.S. headquarters was the largest lease of the quarter, underscoring the continued attractiveness of Boston’s well-established life sciences ecosystem.
Quarterly renewal activity totaled 86,000 sf, which boosted the market’s YTD total to 159,000 sf, a 15.5% decline YOY, though reflecting a 65.3% increase from the second half of 2025. Five transactions in Cambridge accounted for the bulk of renewals YTD at 122,000 sf.
Pricing
Overall average asking rents continued to soften, dropping $1.00 per square foot (psf) QOQ to $78.79 psf, a new cycle-low. This marked a sharper decline of $3.30 psf YOY, though far less pronounced than the $9.00-psf drop posted during the same period between 2024 and 2025. Asking rates for both direct and sublease space contributed to the decrease, falling by $1.01 psf and $0.73 psf, respectively.
