Expedia has blamed a raft of new promotional activity for its failure to hit earnings forecasts for the second quarter.
The travel expert said that revenue had been higher promotions for its member loyalty program and discounts to promote new hotel listings.
The firm recorded quarterly takings of $2.20bn for the three months to 30 June, up 32 per cent on last year, but below forecasts of $2.25bn.
Revenue per room also fell by five per cent, and Expedia warned this would decrease further through the year.
Chief financial officer Mark Okerstrom told Reuters that the firm had also seen business affected by a spate of terror attacks in Europe.
"Travel demand to France is a particular challenge. With each subsequent event we have seen a worsening of the trend," Okerstrom said.
However, he added that bookings from the US into London accelerated once the pound fell against the dollar following the Brexit vote.