Who is the most expensive coach transfer?

Can you tell me who holds the title for the most expensive coach transfer in the world of sports? I'm curious to know which coach has commanded such a hefty fee for their services, and I'm eager to learn more about the circumstances surrounding such a transfer. Was it a highly sought-after manager who brought a wealth of experience and success to their new club? Or was it a surprise move that shocked the industry? I'm intrigued to find out more about this fascinating aspect of the sports world.