Operator Unibet has reported a year-on-year profit after tax decrease of 63% to ¬£23.4m for the first half of 2015.
Profit before tax for the period, which ran from January to June, went down 60% to ¬£26.5m and EBITDA dropped 56% to ¬£33.4m.
Gross winnings revenue increased to ¬£156.6m from ¬£153.6m.
Net cash declined 47% to ¬£12.5m, EBITDA per share fell to ¬£1.17 from ¬£2.67 and earnings per share went down to ¬£0.82 from ¬£2.26.
Unibet CEO Henrik Tjarnstrom said: ‚ÄúIn the period up to 2 August, daily average gross winnings revenue in constant currency was slightly above the daily average of the third quarter of 2014, despite lower margins compared to the exceptionally high margin in July 2014.
‚ÄúUnderlying activity continues to develop extremely positively, with sports betting turnover up 20% in constant currency compared to the same period in 2014, which included the final stages of the World Cup.‚ÄĚ
It was announced in July that Unibet has agreed to acquire the online gambling arm of fellow operator Stan James for a purchase price of ¬£19m, and the deal is expected to be completed in the second half of the third quarter of this year.
Stan James‚Äô approximate 150 Gibraltar-based employees will transfer their employment to Unibet in line with EU rules on business acquisition.