An initial examination by the Irish Payment Services Organisation is showing no fraudulent activity on the credit cards of Supervalu and AXA customers.
It emerged that the card details of some 80,000 clients of getaway break schemes involving those companies were breached.
A third party company based in Ennis, Co Clare, LoyaltyBuild, was the victim of a sophisticated criminal attack, involving hundreds of thousands of credit card holders across Europe.
However, IPSO says it has not found any evidence as yet that the cards have been scammed, although it says its investigation is continuing.
An investigation into the security breach is now being led by the Garda fraud squad which Commissioner Martin Callinan says is being made more difficult and complex by the international dimension.