Mamdani Wants To Turn Lower Manhattan Government Offices Into Nearly 4,000 Apartments

New York City is moving ahead with a plan to replace an aging government office building in Lower Manhattan with nearly 4,000 apartments—a project that could nearly double the number of permanently affordable homes built in the neighborhood over the past decade.

Mayor Zohran Mamdani announced on Sept. 22 that the city had begun public review for the redevelopment of 100 Gold St., a city-owned site that currently houses the Department of Housing Preservation and Development and other municipal agencies.

The winning proposal, from GFP Real Estate, would also replace an existing older-adult center, create roughly 40,000 square feet of public-realm improvements, and add a 40,000-square-foot publicly accessible fitness center.

“Where better to deliver thousands of new homes than the former site of our City's housing agency?” Leila Bozorg, deputy mayor for housing and planning, said. “The redevelopment of 100 Gold will be a major step forward in creating the housing New Yorkers need—including permanently affordable, rent-stabilized homes—in addition to new community space, with no funding from the City.”

That last piece is central to how the project works.

Rather than committing city capital to the development, the project will use a cross-subsidy model, with its roughly 3,000 market-rate apartments helping support approximately 1,000 permanently affordable units.

And there are few places in the country where that model has more potential than Lower Manhattan.

What 100 Gold St. would bring to Lower Manhattan

The property is among more than 100 city-owned sites identified by the Mamdani administration as having the potential to produce more than 50,000 homes.

That would represent a significant piece of Mamdani's "block by block" housing agenda, which calls for building 200,000 new affordable homes and preserving another 200,000 over the next decade.

“New York’s housing crisis demands that we build more—and that we use every tool we have to do it,” Mamdani said. “That means looking at land the City already owns and asking how it can serve New Yorkers better.”

At 100 Gold, the scale and potential are huge even by New York standards.

The updated proposal adds roughly 300 homes to previous plans for the property, according to the city. Once completed, its approximately 1,000 affordable apartments alone would amount to nearly twice as many permanently affordable homes as have been built across Manhattan Community District 1 during the past decade.

“The public amenities add cost and complexity to the project, but it should be manageable,” Joel Berner, senior economist at Realtor.com®, says. “More importantly, the amenities also do political work, because they build community support for a very large project.”

But the redevelopment has also generated controversy during its long planning process.

Community Board 1 officials previously objected to the city's pace and the amount of input residents were given before the parameters of the project were established. Board Chair Tammy Meltzer also criticized an earlier version of the project for setting aside only about one-quarter of the apartments as affordable housing.

The revised proposal still maintains roughly that split of 75% market-rate and 25% affordable units, but it does so at a substantially larger scale.

Lower Manhattan's rents help make the math work

Interestingly, the project's financing depends in large part on the balance of that split.

Manhattan's median asking rent reached $5,117 in the second quarter of 2026, up 9% from a year earlier, according to Realtor.com rental data.

Community District 1, which encompasses the Financial District, Battery Park City, Tribeca, and other parts of Lower Manhattan, is also one of the wealthiest parts of the city.

Median household income there was about $209,000 in 2024, while median renter household income approached $197,000, according to NYU's Furman Center—the highest of any of the city's 59 community districts.

Those economics help underwrite the potential for a cross-subsidy model work. Higher earners can shoulder the burden of high market rents, and that revenue helps offset the lower rents collected from affordable apartments.

“The cross-subsidy model has the advantages of avoiding new capital commitments at a time of tight city budgets and getting units built without waiting on appropriations,” Berner says. “It allows for greater speed of delivery with fewer bureaucratic pinch points.”

But relying on market-rate revenue also means the project's economics are more exposed to changes in the rental market.

“If income streams from the market-rate apartments falter in a rental market downturn, those affordable units will become the focus of serious pressure,” Berner says.

That's to say nothing of the current rent freeze, which is holding rent-stabilized and controlled apartment rents in place for the next two years.

And so, 100 Gold may be a lesson in limits.

“This project might not tell us much about the rest of the [city-owned] sites because 100 Gold St. is likely one of the most desirable ones due to its size and location,” Berner says. “Other city-owned parcels probably won't be able to command the same market-value rents or deliver the same number of units as this large, centrally located one.”

Smaller sites, particularly those in neighborhoods where market-rate rents are lower, may therefore require considerably more direct subsidy to produce the same affordable share.

For now, 100 Gold is moving into the city's formal review process.

A scoping hearing is expected in October as part of the environmental review, which will continue through the fall. The project is then expected to enter the city's Uniform Land Use Review Procedure in 2027, giving Community Board 1, the borough president, City Planning Commission, and City Council opportunities to weigh in before the development can move forward.