Ken Griffin

When it comes to real estate, Ken Griffin spares no expense.

Four years after purchasing Miami waterfront land for a record $363 million and relocating his firms — hedge fund Citadel and market maker Citadel Securities — the billionaire mogul has begun site work on a new headquarters tower. Related Companies will serve as the developer of the 54-story, $2.5 billion high-rise, designed by Pritzker-winning architect Norman Foster.

Griffin’s relocation helped to bolster the city’s real estate sector as his employees bought homes and filled apartments. Griffin also made his own purchases: an $180 million office building in Wynwood and a long, long, long list of trophy residential properties, including a $107 million waterfront estate in Coconut Grove.

The move could yield even greater returns. Griffin partnered with Stephen Ross, another billionaire and Power 100 inductee, to help launch a $10 million campaign to convince CEOs to move their businesses to Florida.

“Where you choose to build a business determines how much time is spent driving growth versus navigating bureaucracy,” Griffin said in a statement while announcing the endeavor. “Miami and the broader South Florida Gold Coast offer deep talent, regulatory clarity and an extraordinary quality of life.”

The billionaire is flexing his muscles, too, in New York via real estate. After Mayor Zohran Mamdani posted a video this April of himself in front Griffin’s penthouse, which cost a record $238 million, touting a 5 percent tax on pieds-à-terre, Griffin, through a representative, threatened to cancel the 62-story Manhattan skyscraper meant to house his companies.

Griffin had been moving aggressively to break ground on a 1.9 million-square-foot glass and steel structure at 350 Park Avenue, moving up the timeline to buy a 60 percent stake from partners Rudin and Vornado Realty Trust.

“It is shameful that he used Ken’s name as the example of those who supposedly aren’t carrying their fair share of the burdens associated with New York City’s often costly and wasteful spending,” Gerald Beeson, Citadel’s COO, wrote to employees. “The project — if we move forward — will entail more than $6 billion of spending.”