Tishman Speyer Provides $25.2M Mezzanine Loan to Refinance 500 Forge

Tishman Speyer Provides $25.2M Mezzanine Loan to Refinance 500 Forge at Arsenal Yards

Watertown, MA — A financing package led by a new real estate debt platform has closed on a $25.2 million mezzanine loan to refinance 500 Forge, a three‑story life science building at Arsenal Yards. The mezzanine piece complements a separate $94.0 million senior loan provided by Landesbank Baden‑Württemberg (LBBW). Proceeds were used mainly to retire the 2021 construction loan and to fund leasing costs tied to a newly secured tenant, Mariana Oncology, a subsidiary of Novartis.

Top-line transaction details

The $25.2 million mezzanine loan was closed by Tishman Speyer and provided to a joint venture led by Boylston Properties together with institutional investors advised by J.P. Morgan Asset Management. The financing package was arranged by JLL Capital Markets’ Debt Advisory team, led by Brett Paulsrud, Henry Schaffer and Geoff Goldstein.

Strategic context for the lender

This transaction represents the first investment from Tishman Speyer’s newly launched real estate debt platform. The platform is aimed at funding institutional‑quality projects in major U.S. cities and plans to provide products such as mezzanine loans, preferred equity, construction financing and loan portfolio acquisitions.

About the property

500 Forge sits on the edge of West Cambridge and Allston within the mixed‑use Arsenal Yards campus in East Watertown. Completed in 2023, the building totals roughly 162,000 square feet across three stories and is now fully leased. Current tenants include Mariana Oncology, Orna Therapeutics and AvenCell Therapeutics.

The building offers advanced lab and office space with interior ceiling heights of 15 to 18 feet, outdoor balconies and covered parking. The design targets life science users with modern infrastructure and tenant amenities.

Why the site matters

Arsenal Yards is a broader, innovation‑driven campus with more than 1 million square feet of labs, offices, retail, restaurants and wellness offerings. The master plan includes retail shops, a seven‑screen theater, more than 300 residences, a 150‑room hotel and significant public open space tied to a revitalized park and regional bike path access. The campus provides proximity to research institutions, venture capital, and a skilled workforce — factors that boost demand for lab and office space in the submarket.

Other local leasing and market activity

Separately, Boylston Properties announced that cell therapy developer SQZ Biotech signed a 63,477‑square‑foot lease at Arsenal Yards and will expand operations there later this year after completing a $72 million Series C and enlarging a collaboration with Roche. Industry brokers note this represents continued life science growth in Watertown, marking multiple new leases in the past 18 months.

The Arsenal Yards development team includes Boylston Properties, Wilder and J.P. Morgan. Boylston has deep local roots and a track record of lab and mixed‑use projects in the Boston area, while Wilder specializes in retail programming and leasing. J.P. Morgan Asset Management serves as an institutional investor with global capabilities and reported assets under management of about $1.7 trillion.

Related development activity

Locally, Tishman Speyer is active in Boston, developing the Harvard Enterprise Research Campus in Allston and previously delivering fully leased life science assets through joint ventures such as Breakthrough Properties. Breakthrough’s holdings include Boston projects like 232 A Street and One Canal in East Cambridge.

Financing team and uses

The refinancing was arranged by JLL Capital Markets’ Debt Advisory group. The combined financing package was structured to replace the original construction loan and to provide capital for tenant‑related costs under the newly executed Mariana Oncology lease.

What this means for the market

The deal highlights continued capital activity for well‑leased life science buildings in Greater Boston, and it signals institutional interest in debt products tailored to lab and office assets. The new debt platform backing the mezzanine piece indicates a lender appetite to provide layered capital solutions for complex projects.