Ken Griffin already did this to Chicago.
Now New York City's socialist mayor is learning what Chicago learned – billionaires don't beg.
And on CNN Tuesday night, Mamdani's own face told you exactly how badly this is going.
The Mayor Who Picked a Fight He Can't Finish
Six weeks ago, Mamdani stood outside Griffin's $238 million Manhattan penthouse on Tax Day and filmed a video calling the Citadel CEO a tax cheat.
Griffin's response was swift and cold.
He called the video "creepy and weird."
He said it raised serious security concerns – pointing out that the CEO of UnitedHealthcare was assassinated just blocks away from that same penthouse.
He said Mamdani "put me in harm's way."
Then he announced Citadel was doubling down on Miami, filing new construction permits and adding hundreds of thousands of square feet of office space – directly because of the mayor's stunt.
https://twitter.com/RedWavePress/status/2059626937127956857?s=20
The $6 billion Park Avenue redevelopment project – the one Vornado's executive vice president called "the best building built in the city by far" – became, in Griffin's words, "a real topic of debate."
That's 6,000 construction jobs and 15,000 permanent jobs sitting on the table while a socialist mayor begs a billionaire to return his calls.
The Grin That Tells You Everything
When CNN's Kaitlan Collins asked Mamdani point-blank if Griffin had responded, Mamdani tried to dodge.
He said he was committed to meeting "any and all business leaders."
He mentioned Jamie Dimon and David Solomon.
He talked about childcare costs and affordability.
Collins pressed him again: "So have you heard back from him, or you have not?"
"Not as of yet," Mamdani said – and grinned.
https://twitter.com/Bubblebathgirl/status/2055488531653411134?s=20
That grin is the whole story.
New York City business leaders have been fleeing to Florida for years, and Mamdani just handed Griffin the perfect excuse to accelerate that exodus.
Griffin Already Did This Once
New York City politicians act like this is a bluff.
It isn't.
Citadel was headquartered in Chicago for more than three decades.
Griffin loved that city – invested in it, built it into a global financial hub, and stayed through decades of rising crime and punishing taxes.
Then Democratic politicians pushed too far.
"Crime and taxes drove us out," Griffin said at a conference last October.
Citadel shrank its Chicago footprint to two floors.
Chicago lost one of its anchor institutions – and the jobs, the tax revenue, the charitable giving, and the civic investment that came with it.
Griffin has donated more than $2 billion to charities in his lifetime.
In New York specifically, he committed $400 million to Memorial Sloan Kettering Cancer Center and another $10 million to help Citadel employees serve on nonprofit boards.
https://twitter.com/breccastoll/status/2059476325455245586?s=20
Mamdani is attacking a man who put $400 million into New York's cancer research.
What Happens Next
Griffin was direct at the Milken Institute conference earlier this month.
"We will add far more jobs in Miami over the next decade as an immediate and direct consequence of the mayor's poor decision," he told CNBC.
When Ken Griffin puts your city's future in the "debate" column, you've already lost the argument.
Chicago's politicians thought Griffin was bluffing too.
Senator Rick Scott put it plainly: Mamdani "cemented NYC's death spiral" the moment he pointed a camera at that penthouse.
The socialist mayor wanted a villain for a Tax Day video.
He found one – and that villain now controls whether 21,000 jobs land in New York or Miami.
The grin Mamdani flashed on CNN Tuesday night is the grin of a man who doesn't understand what he's done.
Griffin understands exactly what he's doing.
Sources:
- Joseph A. Wulfsohn, "Mamdani avoids question on Ken Griffin, admits no response after trying to walk back attack on the billionaire," Fox News, May 27, 2026.
- "Ken Griffin slams NYC Mayor Mamdani over 'personal attack,'" Fox Business, May 2026.
- "Ken Griffin: Citadel expanding in Miami in response to NYC mayor Mamdani's 'tax the rich' video," CNBC, May 6, 2026.
- "Ken Griffin's NYC clash with Mayor Mamdani over taxes echoes Chicago exodus," Fox News, May 2026.
- "Billionaire Ken Griffin says Citadel's Chicago exodus was 'not hard,' cites crime, taxes," Fox Business, October 12, 2025.
- Rick Scott, "Mamdani made Ken Griffin a target – and cemented NYC's death spiral," U.S. Senate, April 2026.