Mass General Brigham signed 105,000 sf, the first tenant lease at Greystar's lab building near Assembly Row in Somerville. The building is 469,000 sf; construction began in 2022 and it was delivered in 2024. The lease covers about 22% of the building (derived), and the first lease arrived roughly two years after delivery (derived).
MGB will consolidate pathology operations and holds expansion rights. Greystar has proposed a second lab building of about 1.4M sf. Nearby, Transmedics took about 500,000 sf at BioMed's Assembly Innovation Park in January.
The first tenant is a health system, not a biotech. MGB is moving operations it already runs, so the demand is clinical consolidation rather than speculative research growth. Compare with the 15.8% mezzanine on a Cambridge lab campus covered Oct. 3.
Implications: Lab buildings near hospital systems have a different tenant base than those chasing biotech. The underwriting question is whether pathology and diagnostics users fill space research users left. Greystar's second building is a bet on the same shift.
Related coverage
Key Takeaways
- When biotech pulls back, the hospital becomes the lab tenant.
- Two years from delivery to first tenant is the carry the sponsor absorbed.
Bisnow, Oct. 1, 2026 · CRE360 analysis: percent leased and carry period derived. Rent, term and TI not disclosed; a project-cost figure in the source was unclear and is not used. Single source.
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