Loyaltybuild Ltd, based in Ennis, is owned by the Affinion Group, a multi- national firm resident in Connecticut.
Credit card details for up to 500,000 people across Europe are believed to have been stolen from Loyaltybuild in a suspected case of data theft in mid-October.
An investigation by the Garda Bureau of Fraud Investigation has been initiated along with probe by the Office of the Data Protection Commissioner.
Last month 46 US states reached a settlement with the Affinion Group after it and two of its subsidiaries were investigated for deceiving customers.
Affinion provided travel packages through loyalty schemes offered by its marketing partners, such as supermarkets, credit card firms, and banks.
However, according to the case against it, the firm improperly rolled over membership packages and wrongly charged customers.
The company agreed to pay €19m in refunds to customers and approximately €11m in penalties. The multi-state settlement was reached without the matter going to trial.