Image courtesy of Watertown Board of Assessors

Newton-based National Development acquired the Watertown Mall for $100 million, closing the chapter on a potential life science redevelopment.

Seller Alexandria Real Estate Equities, the nation’s largest life science landlord, had pursued a partial redevelopment of the property after acquiring the Arsenal Street shopping center in 2021. 

A National Development executive told The Boston Globe the property will continue to operate as a shopping center and the firm plans to make improvements to signage and storefronts.

Alexandria bought the property in April 2021 for $130 million, when demand for life science space was spiraling upwards. In 2022, it submitted a redevelopment plan for three new office-lab buildings totaling 500,000 square feet, and two parking garages replacing surface parking.

Alexandria revised its plans in 2023, as lab demand plummeted following a series of interest rate hikes that depressed investment in the life science sector. The new 1.2 million-square-foot plan added 88 residential units in a building that would have replaced the Best Buy store.

The Watertown assessor’s office valued the property at $67.2 million in fiscal 2025. The 264,549 square-foot mall was built in 1975.

In the past year, lab leasing has gravitated to the industry epicenter of Cambridge, although suburban developers have had some recent success attracting tenants.

In July, Cambridge-based Foghorn Therapeutics leased 72,000 square feet to relocate to 99 Coolidge Ave. in Watertown. The former tennis club was redeveloped as lab space by National Development and Alexandria.

The two firms previously partnered on projects in Boston’s Longwood Medical Area and the 15 Necco St. project in Boston, which was leased by Eli Lilly and Co.

Alexandria has sold several large development sites previously planned for lab projects in recent years, including the Riverside Center office park in Newton and an industrial site in South Boston.