The bloodstock billionaire, dubbed The Boss, is a regular fixture in the winners' enclosure of the sport of kings. Winning is what John Magnier (69) does best.
Synonymous with Coolmore Stud, he made his initial money from his horse-breeding empire, which has world-class farms in Ireland, the United States and Australia.
But his fortune has come from his many investments, which includes buying and selling government and corporate bonds and currency trading. He often teams up with friend JP McManus in his business dealings.
He is married to Susan, the daughter of Irish racehorse-trainer Vincent O'Brien, and they have five children.
In a sport that is dominated by royal families, such as the Dubai-based Al Maktoum family, Saudi Arabia's House of Saud, and the British royal family, the most successful non-royal owner in 2017 was a syndicate owned by Susan. Her syndicate accrued an impressive $9.4m in prize money last year. Horses registered solely to this group won 25 races out of 108 entries, a 23.1pc win ratio - better than any of the royals.
Magnier, the son of a Co Cork landowner, was educated at Glenstal Abbey in Co Limerick but had to leave school at 15 on the death of his father to take charge of the family estate near Fermoy. He later moved to Fethard in Co Tipperary, where he transformed Coolmore Stud into a 7,000-acre multi-million euro business, making millions for himself in the process and becoming Ireland's leading thoroughbred stud owner.
He owns 20pc of UK nursing home group Barchester, which continues to throw off cash. Revenues at Barchester's parent company rose by 5pc to £563.9m in the 12 months to the end of December 31, 2016, according to accounts for UK registered Barchester Healthcare Ltd. Operating profits jumped by £2.8m to £20.9m. Last October, Barchester put a primary care centre beside its Knightsbridge nursing home in Trim, Co Meath, up for sale. The care centre and adjacent nursing home and retirement village is valued at €20m.
Magnier and McManus sold an office and retail building on the exclusive Place Vendome in Paris, beside the Ritz Hotel, for €1bn, with a reported profit of €350m on the deal in late 2016.
Magnier also co-owns with McManus a 23pc stake in €1.82bn-valued Mitchells & Butlers (M&B), Britain's biggest pub group. The company has spent £169m on converting and remodelling 252 sites as well as opening 13 new pubs.
Last year, the bloodstock billionaire and his family acquired the Sutton Scotney Estate in Hampshire for over €52m.
The businessman, who turns 70 next month, has a multi-million pound seafront home on a Caribbean island, where he spends much of his time. His property portfolio stretches from a €30m beach-front pad in Marbella to an interest in the exclusive Sandy Lane Resort in Barbados.