World number three and US Open champion Rory McIlroy has ended his association with management company International Sports Management, they announced today.
The 22-year-old Northern Irishman, golf's brightest young talent, had been with the company from the time he turned professional in 2007.
Manager Andrew 'Chubby' Chandler also handles the careers of world number two Lee Westwood, Open champion Darren Clarke, Masters champion Charl Schwartzel and three-time major winner Ernie Els.
The split was announced two days after McIlroy competed against Clarke, Schwartzel and US PGA champion Keegan Bradley at the PGA Grand Slam of Golf in Bermuda.
He led by three with 12 holes to play, but fell away to a 75 and to third place three behind Schwartzel and four behind winner Bradley.
Chandler, who was in attendance, commented in the company's statement today: "Onward and upwards. We have had a quite brilliant year.
"The company is growing and adapting to ensure it stays at the forefront of golf and the business of managing players. We wish Rory every success."
The statement also said: "It has been an honour representing Rory and we take great pride in the role ISM has played in guiding him successfully through his formative years as a professional golfer.
"Under our management he has grown into an international figure and he leaves us as a major champion.
"ISM prides itself on putting the athlete first. In golf this has enabled our players to achieve unprecedented success with Rory joining Louis Oosthuizen, Charl Schwartzel and Darren Clarke as a major winner and Lee Westwood at the summit of the world rankings.
"ISM continues to go from strength to strength, its dedicated team of professionals providing our clients with world-class support across the globe. We look forward to even more success in the years ahead."
McIlroy had yet to comment either in person, in a statement or via his Twitter site.
He travelled to Bermuda from China and was heading back there for next week's Shanghai Masters, which, although not on any Tour, offers golf's richest first prize of £1.25million.
Chandler has been at McIlroy's side since he joined the paid ranks after winning the silver medal as leading amateur in The Open at Carnoustie four years ago.
As an 18-year-old, he finished third in the Dunhill Links Championship on only his second start, then fourth next time out at the Madrid Masters, but had to wait until the 2009 Dubai Desert Classic for his first victory.
Last season he broke through on the PGA Tour in America, winning the Quail Hollow Championship with a closing 62 two days before his 21st birthday, and then began The Open at St Andrews with a major record-equalling 63.
An 80 followed in windy conditions but, after third-place finishes there and at the USPGA Championship, he found himself centre stage again at The Masters this April.
Three brilliant opening rounds put him four clear, but he then collapsed to a closing 80 and in a traumatic turnaround dropped all the way back to 15th place 10 strokes behind Schwartzel.
Many wondered how long he would carry the scars of that, but then came the US Open at Congressional near Washington, where he broke record after record in winning by eight with a 16-under-par total.
Disappointing finishes of 25th and 64th followed in the last two majors of the season, although at the USPGA Championship he did well to make the cut after injuring his arm hitting a tree root.
By then the youngster was also making headlines off the course, ending a relationship with his long-time girlfriend and starting to date world tennis number one Caroline Wozniacki.
McIlroy, who has come third, third and second in his last three European Tour events, also announced that he would be rejoining the PGA Tour next season.