Michael and Nigel O'Flaherty Estimated worth: €498m Franchises: Mercedes Benz, soon to lose Volkswagen The O'Flaherty brothers' late father Stephen was the pioneer of car distribution in Ireland, striking a deal at the Paris Motor Show in 1949 to bring Volkswagen to this country.
The Waterford man's company Motor Distributors Limited (MDL) went on to bring Renault to Ireland, later selling the franchise to the late Con Smith. He was also responsible for the introduction of Toyota, which he sold to Tim Mahony.
Effective from this October, Volkswagen will take control of the distribution of all new VW, Audi and Skoda cars, bringing to an end the iconic German car-maker's 58-year partnership with MDL. It is estimated that the O'Flaherty brothers will make about €75m from selling back the VW rights. They relinquished the distribution of Mazda last year.
The O'Flahertys still own the Mercedes Franchise, own prime property worth about €325m, manufacture and sell aerial lifts in Britain and the US and, more recently, acquired digital imaging firm C3.
Gemma and Michael Maughan Estimated worth: €265m Franchises: Peugeot and Citroen
Gemma Maughan is the widow of the late Con Smith, a celebrated businessman who headed the Smith Group, which acquired the Peugeot distribution rights in 1969. Smith was killed in a plane crash three years later while leading a trade delegation on behalf of the then Taoiseach Jack Lynch.
Smith's family sold off a number of the group's assets, including the Renault franchise, but retained the rights to Peugeot. It later added Citroen to its business, since renamed Gowan Group.
Gemma, who remains the main shareholder, later married advertising executive Michael Maughan, now chairman of the business. Gowan Group is owned by holding company Convest, which owns a number kitchen and kitchenware brands. Last year, the group bought Senator Windows, Ireland's leading PVC window, door and conservatory manufacturer.
The Maughans also have Dublin property assets and a share portfolio worth about €110m.
Frank Keane Estimated worth: €189m Franchise: Mitsubishi, held the BMW franchise for 36 years to 2003
It was initially speculated that Frank Keane made €34m when he sold the franchise to distribute BMW cars back to the German luxury manufacturer in 2003. It later emerged that he made closer to a fifth of that amount.
Still, cars have made Mr Keane a wealthy man to indulge his interests in fine wines, golf and yachting. His company, Frank Keane Holdings, has acquired significant property assets over the years.
The loss of the BMW rights has seen his focus has switched from distribution to retailing, with his dealership on the Naas Road in Dublin among the five busiest in the country.
Mr Keane remains a distributor in Ireland of Mitsubishi as well as a number of electronics brands, including Pioneer.
Tim Mahony Estimated worth: €151m Franchise: Toyota & Lexus
Tim Mahony bought the rights to distribute Toyota from Motor Distributors Limited in the early 1970s, when the marque had a 0.2pc share of the Irish market.
Since then, Dr Mahony has developed it into the most popular car brand in Ireland, where it has a market share of almost 14.3pc.
The car distribution business has helped Dr Mahony amassed enough to own two golf course estates at one stage through his holding company Killeen Investments and indulge in his acquired passion for horses. He continues to own the exclusive Mount Juliet Estate in Co Kilkenny but sold Fota Island Golf Club in 2004 for a reported €20m.
Bill Cullen Estimated worth: €117m Franchise: His Renault rights are being taken back by the French carmaker next year
Bill Cullen bought the distribution rights for Renault from Waterford Glass for a nominal £1 in 1986, while also shouldering its massive debts.
His bestselling memoirs "It's a Long Way from Penny Apples" in 2001 tells the tale of his humble upbringing in Dublin's north inner city, where he followed in his mother's footsteps to sell fruit on the streets from the age of five.
Mr Cullen began working in the auto industry in 1956 when he took a job as a messenger boy with Waldren's Ford Dealership in Dublin. He was director general of the company within nine years.
Glencullen Distributors, the company through which he holds the Renault rights, sells €250m worth of cars a year. While the loss of the franchise will decimate Glencullen's profitability, Mr Cullen still owns Ireland's leading Renault dealership CityGate Motor Group, which has six locations.
Sources: Irish Independent, The Sunday Times Rich List