US insurer AIG plans a European Union hub in Luxembourg following Britain's decision to leave the bloc, the biggest financial services firm so far to detail such a move. 

AIG said today it will keep its main European headquarters in London and open a subsidiary in Luxembourg.

Luxembourg - along with Frankfurt, Paris, and Dublin - is touting itself as an alternative base for firms wishing to retain access to the EU after Brexit. 

"This ensures AIG is positioned for whatever form the UK's exit from the EU ultimately takes," Anthony Baldwin, Chief Executive of AIG Europe said in a statement. 

The company statement also pointed to an experienced and respected regulator in Luxembourg as one of the attractions of the country.

“Luxembourg, a founding member of the European Union, offers us a secure location in a stable economy with an experienced and well-respected regulator in continental Europe close to many of our major markets,” AIG said.

A spokesman for the company said AIG is not expecting any redundancies in London as part of the move but some senior leadership roles are expected to move to Luxembourg as a result.

Press Association is reporting that fewer than a dozen of its London-based executives could leave the city.

Major banks have said they plan to set up EU subsidiaries to continue to be able to sell their services across the bloc, but few have announced concrete decisions. 

UK bank Lloyds has said it is likely to convert its Berlin branch into a subsidiary.

AIG had previously said it was also looking at Dublin as a possible EU hub and insurer Hiscox has said it will choose between Luxembourg and Malta. 

Lloyd's of London, the world's largest specialty insurance market, is due to pick a location for its EU subsidiary by the end of March, with Dublin and Luxembourg on its shortlist. 

AIG chose Luxembourg for its proximity to the insurer's European clients, position as a founding member of the EU, stable economy and expertise in financial services and "fintech", an AIG spokeswoman said. 

The switch would involve "changes at senior leadership level", she added, without giving more details. 

AIG said the proposed changes were expected to be completed in the first quarter of 2019, subject to regulatory approval.

The insurer currently employs three staff in its Luxembourg office.

Following today’s announcement, Insurance Ireland has called for a review and redoubling of efforts by the Government and its agencies to secure investment opportunities arising from Brexit.

Insurance Ireland CEO Kevin Thompson said: “Ireland has developed into an international hub for insurance with an availability of talent, a well-developed support ecosystem and Single Market access, among many other strengths.

“These strengths must be maximised to avail of any ‘Brexit dividend’ but equally, any deficiencies must also be considered and addressed. It is vital that a review is undertaken of the current interactions of the state and its agencies with prospective international insurance investors.