In an announcement made on 15th April, Shire stated that the move will not result in any changes in the day to day conduct of the company's business, its strategy or dividend policy.

The new holding company will have its primary listing on the London Stock Exchange (LSE) and its American Depositary Shares (ADS) will be traded on NASDAQ. It is not planned that the proposals will result in any job losses or relocation of existing Shire personnel out of the UK.

While the plans are being interpreted by tax experts as an indictment against the UK's corporate tax regime, Shire argued that the proposals are motivated by the fact that the company has become increasingly international, and that only a small proportion of its revenue is now generated within the UK.

"Shire has concluded that its business and its shareholders would be better served by having an international holding company with a group structure that is designed to help protect the group’s taxation position, and better facilitate the group’s financial management. The Directors believe that the most appropriate structure is for the new group parent company to be tax-resident in the Republic of Ireland," the company statement explained.

Corporate tax in the UK was cut to 28% from 30% this year, but whereas the UK once had the third lowest rate in the EU in 1997, it is now the sixth highest, and the effective average corporation tax rate is the eighth highest in the OECD, according to the Confederation of British Industry (CBI). By contrast, corporate tax is 12.5% in Ireland.

The new holding company, which is to be called Shire Limited, will have the same board and management team as Shire, and there will be no substantive changes to corporate governance and investor protection measures, accoridng to the statement.