Bank of Ireland has acquired Florida-based Foreign Currency Exchange Corp (FCE) for €10.7 million.
The bank made the purchase through its First Rate Enterprises subsidiary.
The group said the move gave it a significant foothold in the United States where it is intent on gaining a "material share" of the foreign exchange market.
FCE is a specialised foreign exchange provider, which serves some 200 banks and 1,000 hotels across 46 US states, as well as operating a number of direct outlets.
Senior executives at FCE have been offered generous bonuses to remain with the company.
First Rate is Bank of Ireland's fastest-growing division, generating €23.5 million profits in the half year to September 30th. A joint venture with the British Post Office is ranked top three in the UK's retail foreign exchange market.
First Rate is the largest specialist provider of retail foreign exchange to the domestic sector and holds a majority interest in Global Refunds, a VAT refund firm.
First Rate chief executive Mr Garrett Stokes said the deal would boost the group's profile in the US.
"This acquisition will give us a significant foothold in the United States.
"Application of the very successful First Rate business model to an already successful sales and distribution model by FCE represents an exciting opportunity to capture a material share in this vast market," according to Mr Stokes.
In February, Bank of Ireland said it was shedding 350 jobs in the merger of two loss-making financial advice operations in Britain.
The merger between Chase de Vere and MX Financial Solutions (MXFS) saw the bank write off €140 million as an exceptional charge.
The group has spent an estimated €280 million on expansion in the British financial advice market since acquiring Chase de Vere in 2000.
Bank of Ireland shares closed at €10.25, up 25 cents on the Irish Stock Exchange last night.