Gross profit also declined for the digital marketing service provider, falling 9% to $28.8m.
Operating expenses rose 6% to $15m, while adjusted EBITDA dropped 14% to $19m.
Profit before tax was $14m for the six months ending 30 June, down 22%.
Regulatory updates in the Swedish, German, UK and Swiss markets created new challenges in the year so far, according to the company.
It said the new regulations in Sweden are impacting both volumes and customer sign ups and while it expects this market to stabilise; it does not anticipate revenue to return to previous levels.
In Germany, regulatory uncertainty hangs over the online casino market, where XLMedia saw a decline of 36%.
Share prices of XLMedia dropped from £0.75 ($0.93) to £0.58 following the announcement of its H1 financial results.
On 29 July, the company announced the appointment of Stuart Simms as CEO with effect from 2 October. Experienced with the performance marketing sector, Simms previously worked as CEO of Rakuten Marketing.
XLMedia said its US operations are continuing to develop, last week its US subsidiary, XLMedia US, was accepted as an authorised gaming service provider by the Pennsylvania Gaming Control Board for online advertising of online sports betting and casino brands.
Ory Weihs, CEO at XLMedia, said: “This year has proven to be challenging for both XLMedia and the industry as a whole, as the gaming industry changes and regulates. However, this does result in the group having greater visibility, more sustainable revenues and stable earnings.
“While we expect this disruption to continue in the midterm, we remain committed to our stated strategy, focusing on publishing.”
