Graeme McDowell is set to leave Horizon Sports Management to manage his own affairs. In contrast to the acrimonious departure of world No 1 Rory McIlroy from Horizon last year, McDowell insists he’s leaving on good terms when his contract ends on December 31.

The Ulsterman joined Horizon from Chubby Chandler’s ISM in December 2007 and went on to play in three Ryder Cups and win 11 times, including his first major at the 2010 US Open.

He looks certain to win his fourth Ryder Cup cap next month after a closing 72 left him tied 38th in The Barclays in New Jersey, his last appearance before his wife Kristin is due to give birth to the couple’s first child today.

In a statement issued by Horizon last night, world No 16 McDowell said: “When I joined Horizon in November 2007, I was ranked outside the top 100 players in the world, and was seeking a new and energetic management team to help me achieve my career ambitions — both on and off the golf course.

“I am proud to say that in the intervening years, these ambitions have not only been achieved, but have surpassed my highest expectations.

“During my time with Horizon I have become a Major Champion, played in three successive Ryder Cups and won multiple tournaments around the world.

“In parallel with this, Horizon has helped me to establish a portfolio of global sponsors and corporate partners, with whom I will remain engaged into the future.

“Horizon has also played a key role in establishing and growing the G-MAC Foundation. Its continued work for children’s charitable causes in the years ahead will represent a legacy that the team at Horizon should be genuinely proud of.”

Business interests

McDowell’s business interests have grown in recent years — he has a restaurant, a stake in the Game Golf tracking technology and a clothing brand with Kartel – and he now has his own personal assistant and financial advisors but no plans to move to another management company.

He said: “I am at a stage in my life where it feels right to move on to the next phase of my career – both in golf and business.

“I’m now involved with a growing number of exciting business ventures, many of which Horizon helped me establish, and as the landscape evolves so must I.”

The news will be seen as a blow to Horizon Sports management, who have lost McIlroy, Michael Hoey and Gareth Maybin in recent years and now manage only Shane Lowry and Ross Fisher.

But insiders insist that the McDowell has been ruminating his decision "for months" and that while he was unhappy with the way the McIlroy camp has gone about its business, his decision has no direct connection to the High Court battle between the world No 1 and the boutique agency set up by Conor Ridge.

The Dublin agency has countersued McIlroy for $3 million in unpaid fees and damages after the four-time major winner left them in May last year claiming he signed his contract under “undue influence” when he was just 22 years old and inexperienced.

Horizon also dispute McIlroy’s claim that he paid more than $6.8 million in fees which his lawyers claim was “many times greater” than the norm.

Court case

McDowell confessed at the British Open that his relationship with McIlroy was “strained” by the court case after McIlroy’s lawyers claimed the Portrush man was a shareholder in Horizon Sports management and on a more favourable deal.

Insisting the tension wouldn’t affect their potential Ryder Cup partnership, McDowell said: “Yes, it’s been a strain on our relationship, no doubt about it. We’re not the same as we used to be and until the legal proceedings are over and done with, there’s always going to be that little bit of tension in the air.”

Last night, McDowell added that he was grateful to Horizon for setting him on the path to stardom,

“I would particularly like to thank Conor Ridge and the whole Horizon team for their vision, advice and commitment to my golf career and business affairs over the past seven years,” he said in a statement.

“Their integrity and professionalism are a mark of everything that Horizon represents. I look forward to their continued friendship and support in the years ahead.”

Horizon boss, Conor Ridge wished McDowell well, explaining: “ He took a leap of faith when joining what was then a fledgling Irish sports management agency, and we are immensely proud of what we have achieved together since.”