Former world number one golfer Rory McIlroy has left his Dublin-based management company Horizon Sports Management to set up one of his own.

The 24-year-old from Co Down has set up Rory McIlroy Incorporated (RMI). His contract with Horizon, headed by Irishman Conor Ridge, had four more years to run.

Both sides said last night that the matter was now in the hands of their legal teams.

In a statement issued yesterday, McIlroy said businessman Donal Casey would act as chief executive of RMI. Mr Casey is an actuary by profession and has experience of being a chief executive.

The statement said media relations would be handled by a team from the Communications Clinic, led by Terry Prone.

"Rory McIlroy today confirmed he has terminated his contract with Horizon Sports Management and that the details of the termination are in the hands of a legal team led by A&L Goodbody in Dublin, Ireland, " the statement said.

Horizon also issued a statement and expressed its "disappointment" at McIlroy's decision. It said that it was involved in one of the most lucrative agreements in sport when McIlroy signed a deal with sports company Nike, reputedly for $100 million.

McIlroy’s form has been relatively poor this year and his prize money earnings have fallen dramatically.