Ken Griffin’s hedge fund is looking to spread out in Miami’s most anticipated office tower.

Citadel signed on for two more floors at 830 Brickell, the under-construction tower in Miami’s financial district that was a magnet for pandemic-era corporate expansions. The hedge fund will be the largest tenant in the building, with 130K SF across eight floors.

A Citadel spokesperson confirmed the details of the lease to Bisnow, declining to comment further. The deal was first reported by Bloomberg.

The 640K SF tower was originally slated for delivery in 2022, but its opening has been delayed, and no companies occupy their offices yet. The developers said in a statement that tenants have started building out spaces and are expected to begin moving in during the third quarter.

“830 Brickell office tower has achieved its initial Temporary Certificate of Occupancy (TCO), representing a significant milestone as Miami’s first Class A+ office tower advances towards completion,” the tower’s developers, OKO Group and Cain International, said in a statement. “The 57-story tower is fully leased to a roster of best-in-class tenants, 90 percent of which are new to the Miami market.”

Citadel, which leased 90K SF in the building in August 2022, is subleasing the additional space from Kirkland & Ellis. Chicago-based Kirkland, the biggest law firm in the world by revenue, started marketing the 14th and 15th floors a year ago after leasing 115K SF four months after Citadel for its first Miami office.

Kirkland traded those floors for space higher up in the building after Winston & Strawn, another Chicago law firm, gave up space at the tower, according to Bloomberg.

Rent for the sublease space approached $200 per SF and was among the most expensive in the city, brokers previously told Bisnow.

Citadel expects to have around 450 employees in Miami by the end of the summer, according to Bloomberg, roughly two years after Griffin announced he was moving Citadel and Citadel Securities from Chicago to Miami.

The hedge fund has been operating out of temporary office space at 200 S. Biscayne Blvd., known as Southeast Financial Center, while it awaits the delivery of 830 Brickell.

Griffin ultimately plans to build his own office tower for Citadel's headquarters, potentially including a hotel, at 1201 Brickell Bay Drive. The billionaire spent $363M on the vacant development site in April 2022 and has tapped Foster + Partners to design a tower, which is expected to be one of the tallest buildings in Miami.

The Citadel founder is also partnering with Vornado Realty Trust and Rudin on a 62-story tower at 350 Park Ave. in New York that would hold more than 800K SF of office space for Citadel and Citadel Securities.

A Cushman & Wakefield team of Brian Gale, Ryan Holtzman and Andrew Trench handle leasing at 830 Brickell. A spokesperson for the firm declined to comment.

830 Brickell has been under development since 2016. OKO and Cain secured a $300M construction loan for the project in August 2019, when it had a scheduled delivery in the first quarter of 2022.

The tower attracted several high-profile tenants before Citadel leased its first six floors in August 2022, including Microsoft and Thoma Bravo. But the hedge fund’s lease at the tower helped spur more deals at the property.

Insurance firm Marsh, A-CAP, a New York-based hedge fund and Toronto-based wealth manager CI Financial have also signed on for space. WeWork was the first committed tenant in the tower before the landlord reportedly bought back the space due to high demand.

Brickell has long been Miami’s financial hub and among its most expensive markets, and its asking rates — at $102.39 per SF for Class-A space, according to Cushman & Wakefield — are among the highest in the country.

The tower’s successful lease-up has inspired several other developers to propose Brickell office towers. Swire Properties and Related Cos. have plans for the 1,000-foot-tall One Brickell City Centre, although recent Wall Street Journal reporting suggests the project has been put on hold while the developers search for an anchor tenant.

Santander has filed plans to replace a 14-story office building it owns in the neighborhood with a 40-story tower. But the Madrid-based bank has also signaled its intention to land tenants before beginning construction. A representative told Bisnow in February that the bank was merely exploring all options at the site.

While most of 830 Brickell's space was gobbled up in big chunks, the market today is dominated by smaller deals and local firms, none of which has been enough to spur the construction of a new tower.

830 Brickell was the first new office tower to break ground in the neighborhood in more than a decade. Demand for multifloor office leases is likely to determine when the next tower goes vertical.