Former US Open champion Graeme McDowell will leave the Horizon Sports stable when his contract finishes at the end of the year in order to manage his own commercial interests, the world number 16 has announced.
"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," the Northern Irishman said in a statement.
"I am proud to say that in the intervening years these ambitions have not only been achieved but have surpassed my highest expectations," McDowell added after finishing 11 strokes behind winner Hunter Mahan at The Barclays tournament on Sunday.
McDowell sealed his only major triumph in 2010 and is hoping to make his fourth consecutive appearance in Europe's Ryder Cup team at Gleneagles next month.
"During my time with Horizon, I have become a major champion, played in three successive Ryder Cups and won multiple tournaments around the world," the 35-year-old 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."
Rory McIlroy, the world number one and McDowell's Ryder Cup playing partner, is a former member of the Horizon stable.


McDowell will sit out the Deutsche Bank Championship in Boston after becoming a father on Monday.

The Northern Irishman's wife Kristin underwent a planned cesarean and 35-year-old McDowell duly tweeted about his new arrival.

He wrote: "Thanks so much for all the well wishes. Mum and baby girl are happy and healthy. Happiest moment of my life hands down. #daddy #love."

Having completed his final round at the BMW Championship on Sunday, McDowell told the Golf Channel: "My caddie has been telling me all year 'You're not going to want to go to Boston', so I've decided to give myself the weekend off and just be with the family. Nice to be able to plan it that way."

By missing Friday's Deutsche Bank, McDowell will not be able to advance his current FedEx Cup standing of 40th, while he also has a Ryder Cup slot to protect on the world points list.