Royal London has opened an Irish subsidiary as a direct result of Brexit.
The insurance firm is to create 20 new jobs in Dublin as a result, as well as retaining all previous employees.
Royal London says the Irish subsidiary will allow it to continue to compete for new life insurance business in Ireland, and to administer existing Irish and German policies.
These were bought by customers who lived outside the UK, and may be impacted by Brexit.
It says Irish customers will also benefit from strengthened governance and full regulatory oversight by the Central Bank of Ireland
Tim Harris is chairman of Royal London Insurance DAC: "We are writing a new chapter in the success story of Royal London in Ireland.
"In its chosen markets our Irish business has grown from less than 4% market share in 2012 to over 18% market share in the first nine months of 2018.
"This growth has been achieved by a highly customer-focused team providing a market-leading product and service offering.
"By setting up this subsidiary, we intend to grow our Irish business further and to see it thrive as an integral part of the Royal London family."
Royal London is the largest mutual life, pensions and investment company in the UK and employs 3,745 people.
The firm, formerly called Caledonian Life in Ireland, has had a presence in Dublin since 1824.