Quinn Financial Services, part of the Quinn Group of companies, is to take a stake in the NCB Group.
The announcement was made today following the approval of a management-led buyout of NCB by the Irish Financial Services Regulatory Authority.
NCB's management team had indicated that it was looking for an investor to acquire a shareholding following closure of the deal with the stockbroker's former owner Ulster Bank.
The Quinn deal is subject to regulatory approval.
The Quinn Group, was founded by Sean Quinn 30 years ago as a producer of quarry products, but has now diversified into one of Ireland's most successful companies with interests in container glass production, general insurance and pensions, hotels and public houses. The Quinn group employs 2,600 people.
Quinn Direct, the insurance business launched in 1996, is now the fifth-largest general insurer in Ireland.