William Hill’s share price fell by more than eight per cent in Friday’s trading after it warned full-year profits would be near the bottom of the analyst consensus range of £290.9m to £312.1m.
The bookmaker - which employs 3,000 people in Yorkshire - said operating profit for the three months to September 30 was down 39 per cent.
Net revenue fell nine per cent in what was a “tough quarter” for the betting firm, partly due to a £23m hit from new gambling duties.
It comes one day after its major UK rival Ladbrokes reported its third-quarter profits fell 57 per cent.
Ladbrokes also blamed taxes for slicing into margins. It also cited marketing costs ahead of its proposed £2.3bn Gala Coral merger as hitting its performance.
Both William Hill and Ladbrokes said their figures were hampered by comparisons to a bumper third quarter last year, which was bolstered by huge gambling activity during the football World Cup.
Chief executive James Henderson said: “Q3 was always going to be a tough quarter given last year’s World Cup and very strong gross win margin, allied to £23m of additional gambling duties this year.”
Mr Henderson said the quarter was also hit by weaker-than-expected sporting results, which impacted retail, the US and Australia.
However, he said growth in William Hill’s online core markets of the UK, Italy and Spain remained strong for betting and gaming.
Mr Henderson added that although cost discipline had “partially offset” weaker performance, the board expects full-year profit to be at the bottom of analysts’ consensus range.
William Hill is a major employer in Yorkshire, with more than a fifth of its global workforce in the region.
It employs 1,300 alone in Leeds, mainly in its technical and trading teams.