Shares in Evoke PLC (LSE:EVOK) fell almost 9% after the William Hill owner warned that first-half profits would come in below expectations.
Adjusted EBITDA for the first six months of the year are now guided to be around £35-40 million "behind plan", with full-year results also likely to be hit too.
The statement from the company formerly known as 888 Holdings revealed lower-than-expected revenues in the second quarter, combined with higher marketing costs and the timing of cost-saving actions.
UK bookmaking shop revenue was down 8% year-on-year, though stable compared to the second half of last year, while UK online revenue climbed 3% and international revenue rose 2%.
CEO Per Widerström said: "Whilst it is disappointing that the first half financials are behind our plan, the underlying health of the business is getting stronger, and the corrective actions we have already taken make us even more confident that our strategic approach is sound and will achieve sustainable success."
He added: "We are undertaking a complete reset and transformation of the business, and the scale of change is significant but necessary. This transformation will take time but will enhance operational efficiency, leading to a bigger, more profitable and more cash-generative business in the future."
The board plans to improve the UK retail performance with a change of leadership and "new future-proof gaming machines" rolling out towards the end of this year.
Evoke said revenues in the second half were expected to be in line with medium-term guidance of 5-9% and said its cost-cutting programme should result in £30 million of savings this year, weighted to the second half.