Developer seeks to alter office/condo mix in $1.3b Winthrop Center already under construction

An updated rendering of the Winthrop Center tower, under construction in the Financial District. MIllennium Partners

Construction is well underway on a skyscraper in Winthrop Square that will be Downtown Boston’s tallest building (and the city’s fourth-tallest). But the details of what it will house continue to evolve.

On Monday, Millennium Partners told the city it wants to tweak the mix of housing and office space in the Winthrop Center tower that it’s building on Federal Street in the Financial District.

The developer would reduce the amount of space devoted to condominiums by nearly 100,000 square feet while increasing office space by 22,000 square feet and eliminating a planned conference center.

Overall, the tower would lose about 110,000 square feet from what was approved in May 2018, making it 1.55 million square feet. It would remain the same height: 691 feet.

A new rendering of the Winthrop Center project. MIllennium Partners

The $1.3 billion project, which broke ground about a year ago, is on track to open in 2022. With construction crews still working on the foundation, there’s time to tweak the design of the floors above, said Joe Larkin, who’s leading the project for Millennium. The company has been talking with potential office tenants and studying the condo market to make sure it delivers what people are looking for, he said.

“Just because we get our building permit doesn’t mean we don’t stop trying to make the building even better,” Larkin said. “We’ve been talking to a lot of tenants, and we know what they want in an office.”

A past rendering of the Winthrop Center project from the BPDA board meeting in May 2018. MIllennium Partners

The proposed changes matter, in part, because the price Millennium will pay the city to buy the site — formerly a shuttered municipal garage — includes $100 for every square foot of condominiums the company sells. If the changes are approved, Millennium would reduce the saleable residential square footage by 37,286, worth $3.7 million to the city, bringing the final purchase price to about $160 million.

The developer would make up for much of that by contributing another $3 million to an affordable housing project in Chinatown that Millennium is building along with the Asian Community Development Corporation.

In a sign of the close scrutiny the Winthrop Square project has received for years, even the relatively minor proposed changes will undergo review by the Boston Planning & Development Agency. A public meeting has been scheduled for Wednesday, and comments will be taken through Nov. 12.