Paddy Power Betfair has said that the unexpected victory of Donald Trump in the US presidential election in November cost the group almost £5m.
In a trading update for the three months to the end of December, the bookies chain said that it continued to see good sportsbook staking growth but the results favoured customers.
"We estimate that the impact on group revenue from the customer friendly results, before any benefit from the re-cycling of winnings, was approximately £40m in the quarter," the company said.
It added that impact on profitability of these results was partially offset by lower than expected marketing and staff costs.
Paddy Power Betfair said that its group revenue for the full year was up 18% year on year to £1.551 billion.
It also estimated that its full-year earnings hit the mid-point of its guidance despite the run of adverse sports results at the end of the year, pointing to the underlying strength of the recently merged business.
The company in November raised its full-year core earnings (EBITDA) forecast to a range of £390-405m from a previous range of £365-385m citing a boost in the sterling value of its euro revenue, last year's merger and favourable sporting results.
Paddy Power Betfair, which has a chain of shops as well as an online business, said its online revenue fell 3% but were up 18% in its Australian business.
The company is due to report its full year results on February 7.
Rival William Hill said this month that its annual profits would fall to the bottom of its forecast range while the recently merged Ladbrokes Coral Group said it would meet its guidance.