"The relatively much stronger fourth-quarter results by Priceline suggest to us significantly increased competitive risk (for Expedia) and possibly execution challenges," Citi Investment Research analyst Mark Mahaney wrote in a note to investors.

UBS Investment Research analyst Kevin Crissey called Expedia's results appear to mirror the overall deterioration in travel demand.

"Expedia is not a market-share story like Priceline and is unlikely to perform better than the overall (online travel agent) universe, in our view," Crissey added.

The companies' divergent fortunes were most apparent in their airline bookings during the quarter.

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