Paddy Power-owner Flutter has announced plans to cut up to 1,400 jobs as its boss claimed the company "cannot fully absorb" tax rises imposed on the gambling industry.
Staff based in the UK and Ireland, as well as British and Irish workers at Flutter's sites in Portugal and Romania will be affected, but what roles are at risk has not been disclosed.
The government announced increased taxes on online casino and sports betting, with an exemption for horse racing, in the Budget last November.
Flutter boss Kevin Harrington said the tax hikes had "fundamentally changed" the economic model of the UK betting and gaming industry, arguing it had helped "fuel the unlicensed, unregulated market".
"We continue to expect these tax increases to have a very significant impact on the overall market," Flutter said on Tuesday.