US Open champion Rory McIlory is expected to join compatriot Graeme McDowell at management company Horizon Sports following his split with International Sports Management.
The 22-year-old had been affiliated with the company, headed by Andrew 'Chubby' Chandler, since turning professional in 2007.
Chandler and ISM have had an enormously successful year with their clients winning three of the four golf majors.
McIlroy won the US Open in June while Charl Schwartzel and Darren Clarke won the US Masters and British Open respectively.
"I am now keen to move on to the next stage of my career and I feel this will be facilitated by a fresh view and a new structure around me," McIlroy said in a statement.
"Chubby and his team have played a very important role in my success to date and I have made great progress under their management and for that I will always be grateful."
McIlroy recently took part in the Grand Slam of Golf in Bermuda, a two-round event which features the four major winners.
The Northern Irishman was set to be the first European since Ian Woosnam in 1991 to win the title but threw away his lead. The event was won by American Keegan Bradley, winner of the 2011 USPGA Championship.
