Ken Griffin appears to be making good on his promise to “double down” on Miami — just weeks after he became the unwitting face of Mayor Zohran Mamdani’s campaign to tax the rich.

The billionaire Citadel founder has expanded plans for his sprawling Miami development after publicly feuding with the democratic socialist mayor over New York’s newly enacted pied-à-terre tax, according to Bloomberg News.

The latest proposal adds a 300-unit apartment tower, a 1,420-space parking garage and additional office space to Griffin’s growing real estate empire in Miami’s Brickell financial district.

Griffin has also acquired all of the units in a 22-story condominium building across the street from the planned headquarters and intends to demolish the structure to make way for future development, Bloomberg reported.

The move is the clearest sign yet that Griffin is backing up his threats to steer more investment toward Florida following his clash with Mamdani.

The feud erupted in April when Mamdani filmed a viral Tax Day video outside Griffin’s Manhattan penthouse at 220 Central Park South, citing the financier by name as he used the $238 million apartment as an example of the type of property that would be affected by the levy.

Griffin fired back, calling the stunt “creepy” and warning that New York was sending the wrong message to investors and employers.

Jay Batra, CEO of Batra Real Estate and Batra Property Management, who works in both New York and Miami, told The Post that the bigger issue may not be the tax itself but the attention surrounding it.

“I think the pied-à-terre tax itself will do less damage than the publicity that this has generated,” Batra said, adding that many affluent buyers are increasingly asking whether there are other cities where they would rather “park” their money.

Griffin has spent years assembling land in Brickell, where he now controls roughly five acres spanning two city blocks. The latest changes would make the project even more office-focused than originally envisioned.

A hotel that had previously been planned for one of the towers has been removed from the proposal in favor of additional commercial space, according to Bloomberg.

“We are focusing this part of our development at 1201 Brickell solely on commercial office space,” a Citadel spokesperson told the outlet.

“Miami is open for business, and the unparalleled quality of our development will drive the tenancy of leading global firms, including Citadel and Citadel Securities.”

The expanded plans come just weeks after Griffin publicly sparred with Mamdani over New York’s newly enacted pied-à-terre tax on luxury second homes.

At the Milken Institute Global Conference in Beverly Hills last month, Griffin suggested the episode had reinforced his commitment to Florida.

“What the mayor of New York has made clear to my partners, and principally my New York partners, is that we need to double down on our bet in Miami,” he said.

The Citadel chief also raised questions about the future of the firm’s planned involvement in the 350 Park Ave. office tower project in Manhattan, while Citadel chief operating officer Gerald Beeson criticized Mamdani’s actions as “shameful.”

The dispute quickly became a proxy fight over whether New York’s tax-the-rich policies risk driving away wealthy investors and businesses.

Last month, Business Insider estimated that Griffin’s three New York residences — including his $238 million penthouse at 220 Central Park South and two apartments at 740 Park Ave. — could leave him with an additional $1.3 million to $1.4 million annual tax bill under the new law.

City and state officials have projected that the pied-à-terre tax will generate between $340 million and $500 million in annual revenue.

Batra said he has seen hesitation among prospective luxury buyers as the debate over taxing wealthy homeowners intensifies.

“I am negotiating deals and working with buyers who are in the 1% and they don’t like what they’re hearing,” he told The Post.

“It’s not helpful to a buyer, definitely not helpful to a seller. It’s not helpful to real estate professionals who are on the ground working so hard to facilitate deals.”

The broker, who recently worked with buyers considering properties in the Upper West Side and SoHo in the roughly $10 million range, said Miami is benefiting from the contrast.

“It’s certainly helping Miami real estate,” Batra said. “Miami is on the map.”

The Post has sought comment from Citadel and Mamdani.