WASHINGTON, May 5 (Reuters) - Hedge fund Citadel is "doubling down" on its Miami ventures, revising its plans in the city to make the firm's office building larger, CEO Ken Griffin said at the 2026 Milken Institute Conference on Tuesday.

Griffin was responding to questions about New York City Mayor Zohran Mamdani, a democratic socialist, who in April ‌filmed a video titled, "Happy Tax Day, New York. We're taxing the rich," in front of Griffin's penthouse.

Griffin said during the Milken event that Mamdani's video in front of his home was "creepy and weird."

The new tax, which would impose an added annual charge on second houses, condos and co-ops valued at over $5 million if the owner doesn't list them as their permanent residence, fuels the debate over a potential exodus of New York City's mega-rich.

"You know, Mamdani's making it really clear: New York doesn't welcome success," Griffin said on Tuesday. "Are these states trying to push away from their populations those who really do believe in the merits of capitalism, the merits of a free society, the importance of education?"

When asked about Citadel's plans for its massive office redevelopment project in Midtown Manhattan, Griffin said the project was "still a point of discussion internally." Meanwhile the firm has revised its plans to expand its Miami office, he added.

Mamdani's office did not immediately respond to a request for comment.

Griffin said separately that the Federal Reserve is unlikely to cut its key interest rate, as inflation has persisted on elevated energy prices during the Iran war stalemate.

"So from that vantage point, I think the arguments that we saw - and it's hard to believe, just eight weeks ago, 10 weeks ago - that we needed to cut rates further this year are looking a bit dated at this point in time," he said.