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ATERTOWN, MA – The Watertown Mall, once slated for a major life‑sciences overhaul, will stay a shopping center after Newton‑based National Development bought the 18‑acre site for $100 million. The transaction closed on Oct. 16, following Alexandria Real Estate Equities’ 2021 purchase of the property for $130 million. The deal signals a strategic pivot amid Boston’s cooling lab market.

    Alexandria had planned to convert the mall—home to Best Buy and Target—into roughly 500,000 sq ft of laboratory and office space, coupled with retail. That vision reflected the near‑zero vacancy rates and high demand for labs three years ago. Today, CBRE reports a 27.7 % vacancy rate for Boston labs, and lease rates have dropped to about $85 per square foot from $100. The slump has left at least 20 lab buildings empty and 12 million sq ft of office space unoccupied, underscoring broader commercial challenges.

    Watertown’s life‑sciences boom has largely centered on Arsenal Street, where the former Arsenal Mall and new projects like Arsenal on the Charles have added mixed‑use and lab space. National Development, known for Boston’s Ink Block, has yet to disclose its long‑term plans for the mall. Neither company responded to requests for comment.

    The sale marks a shift away from speculative lab conversions toward more stable, income‑generating retail and mixed‑use developments, signaling a turning point for Watertown’s flagship property and the broader Greater Boston lab market.