Almost one-fifth of wholesale finance activity in the European Union could take place in the Republic of Ireland post-Brexit, a Brussels-based think tank has projected.
Bruegel said 2% of EU's wholesale activity was currently in the Republic, versus 90% in the UK, but this could increase to 15% or 18% once the UK leaves.
The report estimates that around €1.8trn of UK banking assets will be on the move post-Brexit, with about 35% of London wholesale banking currently relating to clients in the other 27 EU member states.
That varies from about one-fifth for UK-headquartered banks, to one-third for US and half for EU banks.
"Thus, about €1.8trn, or 17%, of all UK banking assets might be on the move as a direct consequence of Brexit," the report said.
It also claimed that about 10,000 banking jobs and 20,000 related professional services roles could be up for grabs by other EU capitals, with Dublin, Frankfurt, Paris and Amsterdam among the cities listed. However, other cities including Brussels, Luxembourg, Warsaw, Milan and Vienna could also feature.
The report presents two scenarios for post-Brexit capital markets services - an integrated wholesale market, or one that fragments along national lines.
"In both scenarios, the UK's share of the European wholesale market drops from 90% to 60% because of Brexit," the report said.
"The starting point is that financial firms with a MiFID passport can serve EU27 clients from anywhere in the EU27, just as they currently do from London."
The report, co-authored by Andre Sapir, Dirk Schoenmaker and Nicolas Veron, said that in the fragmented case, Frankfurt, which hosts the biggest European operations of the US investment banks outside London and is home to the European Central Bank, would become the main centre, with 45% of the EU27 wholesale market.
Paris, home to the European Securities and Markets Authority and several large banks, may cover 20%, and Dublin and Amsterdam might cover 15% and 10% .
In scenarios that assume integration, there is less need for all activities in one location. In this case, 35% of wholesale finance would be in Frankfurt, and 12 to 20% each in Amsterdam and Paris, with Dublin getting 18%.
The report came a day after a French politician warned Britain would lose crucial EU financial access rights during a visit to London to poach bankers and financiers. Valerie Pecresse, president of Ile-de-France, said Brexit is opening up "fierce competition" between Europe's capitals to take business from the City.