On Thursday, in an email to employees, the billionaire wrote that both the hedge fund Citadel and the market maker Citadel Securities would be establishing new headquarters in Miami, “a vibrant, growing metropolis that embodies the American Dream—embracing the possibilities of what can be achieved by a community working to build a future together.”

The headquarters, expected to be based in a new tower being built on Miami’s Brickell Bay, will be constructed over the coming years. In the meantime, Citadel and Citadel Securities plan to lease space in the city, with the expectation that a few hundred employees will be based there come 2023. The two companies have more than 1,000 employees currently based in Illinois.

While Citadel and Citadel Securities plan to maintain a presence in Chicago, the firms’ impending departures mark the latest in a string of exits from the city. Boeing recently unveiled plans to move its headquarters to Arlington, Va., after 20 years in the city. And Caterpillar, a company that has been based in Illinois—primarily in downstate Peoria—for 90-plus years, has announced that it, too, is moving out of nearby Deerfield, Ill., in favor of Irving, Texas.

Griffin first moved to Chicago soon after graduating from Harvard. It was there, in 1990, where he started Citadel, and, a dozen years later, where he founded Citadel Securities. Both Citadel and Citadel Securities have since become integral players on Wall Street in their own respects, as well as within Chicago and Illinois. Griffin alone has donated more than $600 million to organizations in the city, and the company and its employees have likely paid billions in taxes. “Chicago will continue to be important to the future of Citadel, as many of our colleagues have deep ties to Illinois,” Griffin wrote in the email to employees. “Over the past year, however, many of our Chicago teams have asked to relocate to Miami, New York, and our other offices around the world.”

However, in recent years, Griffin has warned several times that Citadel and Citadel Securities may be on the hunt for a new home base. Often citing the violence and political environment, Griffin has seemingly grown frustrated with the city and state’s political leadership, telling Bloomberg in May that “we’re getting to the point that if things don’t change, we’re gone.” One of the Republican Party’s largest donors, Griffin has also become a central power in the state’s upcoming governor race, pouring millions into the campaign of Aurora Mayor Richard Irvin in a bid to unseat current Gov. J.B. Pritzker. Griffin was also a driving factor behind the campaigns of former Illinois Gov. Bruce Rauner, a Republican.

In Miami, Citadel and Citadel Securities are joining a flock of other big-name finance firms like Elliott Management, Goldman Sachs, and Blackstone that have made a push to expand in South Florida over the course of the COVID-19 pandemic. Citadel Securities was on the earliest wave of the move at the outset of 2020 when it set up a trading floor at the Four Seasons Palm Beach hotel. Griffin, a native of Florida who was born in Daytona Beach and attended middle and high school in Boca Raton, has moved his family to Miami recently, as well.

“Chicago has been a remarkable home for Citadel. I still remember the incredible civic pride and engagement when I arrived more than thirty years ago—and the outreach by business and political leaders who wanted us to succeed and be a part of the fabric of Chicago’s community,” Griffin wrote. “That ethos served us well in building our firm—and I am proud of all that we have contributed to Chicago over the past three decades. I hope we continue to make such a meaningful impact in all the cities around the world that we call home.”

Fortune obtained the text of Griffin’s email detailing the move to employees that was sent Thursday. A copy of it is below:

Dear Colleagues,

I am excited to share with you that Citadel is moving its global headquarters to Miami. Miami is a vibrant, growing metropolis that embodies the American Dream—embracing the possibilities of what can be achieved by a community working to build a future together. I am excited to have recently moved to Miami with my family and look forward to rapidly expanding Citadel in a city so rich in diversity and abounding with energy.

Chicago will continue to be important to the future of Citadel, as many of our colleagues have deep ties to Illinois. Over the past year, however, many of our Chicago teams have asked to relocate to Miami, New York and our other offices around the world. With our new office opening at 425 Park Avenue, our expansion at 350 Park Avenue and our new headquarters opening on Brickell Bay, in the heart of Miami’s booming financial district, we are in a strong position to support these transitions. We recognize that the choice of where to call home involves personal, family, school and other considerations, and we will provide comprehensive support to meet the needs of our teams.

Chicago has been a remarkable home for Citadel. I still remember the incredible civic pride and engagement when I arrived more than thirty years ago—and the outreach by business and political leaders who wanted us to succeed and be a part of the fabric of Chicago’s community. That ethos served us well in building our firm—and I am proud of all that we have contributed to Chicago over the past three decades. I hope we continue to make such a meaningful impact in all the cities around the world that we call home.

With excitement for what is ahead,

Ken