US Open champion Rory McIlroy has split with his manager Andrew Chandler.
The 22-year-old Northern Irishman has been with Chandler’s International Sports Management company since turning professional in 2007.
A spokesman for ISM said: “There has been no falling out, it is amicable. He is joining his great friend Graeme McDowell at Horizon.”
In a statement, Chandler said: “We have had a brilliant year. Rory has grown and he leaves us as a major champion.”
McIlroy became the youngest winner of the US Open since Bobby Jones in 1923 when he won by eight shots at Congressional in June.
It capped a remarkable four years of golf for the world number three who turned professional after the 2007 Walker Cup.