The steady climb of commercial property assessed clean energy (C-PACE) financing around the U.S. has made its way to one of Boston’s tallest buildings. 

Millennium Partners has secured a $281 million C-PACE loan to implement energy efficiency upgrades at the 62-story Winthrop Center in Downtown Boston, the developer announced Friday afternoon.

Nuveen Green Capital originated the fixed-rate loan under the Property Assessed Clean Energy (PACE) Massachusetts program which marked the largest C-PACE financing to date in the New England region, according to the lender.,.  

The condo inventory of the roughly 800,000 square-foot mixed-use building completed in 2023 attracted strong lender competition with many debt funds chasing the loan, according to a source familiar with the transaction. 

The C-PACE debt closed concurrently with a $575 million commercial mortgage backed securities (CMBS) loan led by Morgan Stanley for the office and retail portion of the tower according to a presale report from Moody’s. CoStar first reported the MP Trust 2026-WTRP single-asset-single-borrower deal for Boston’s largest building in the city’s financial district.  

The combined $856 million debt package takes out a prior construction loan from Cale Street in October 2020 after the London firm stepped in following another bank who  backed out during the height of the COVID-19 pandemic, according to sources. 

“We were honored to partner with MassDevelopment to recapitalize the largest C-PACE-financed project in New England, one that has helped reshape downtown Boston with state-of-the-art, energy-efficient residences,” Mike Doty, senior director of originations for NGC, said in a statement. 

Christopher M. Jeffries, founder of Millennium Partners, said in a statement that the C-PACE loan “recognizes the investments we have made in energy efficiency while providing long-term capital that supports the building’s enduring performance.”

The PACE Massachusetts program was updated in June 2026 by MassDevelopment, in partnership with the Massachusetts Department of Energy Resources to set financing levels for new construction projects based on the project’s compliance with the local building codes. 

Andrew Coen can be reached at acoen@commercialobserver.com.