Rupert Evans, international head of credit and financial risks reinsurance, will move from London to New York as part of the reorganisation.
Marsh will offer insurance brokerage services, covering Nu Stadium and the wider Miami Freedom Park project.
The change is set to add underwriting capacity and expertise across several commercial insurance lines.
Nick Goepp steps into the western excess casualty post and Lexi Bueno has been selected to oversee the Central US risk management team.
