The Momondo Group has sold to the Priceline Group, owner of rival travel search service Kayak, in a $550 million deal.
The deal will see the two brands within the group, Momondo and Cheapflights, "roll under" the Kayak division.
Regulatory approvals are needed to close the acquisition, a statement says, with it expected to wrap up by the end of 2017.
Kayak CEO Steve Hafner will have responsibility for all of Priceline Group's travel search brands.
Priceline Group president and CEO, Glenn Fogel says "metasearch is appealing to consumers and we're keen to expand our global footprint".
"Momondo and Cheapflights will be nice additions to our meta portfolio under Kayak."
The deal gives the Priceline Group a head-start in a few of the markets where it has failed to achieve any significant traction over the years, primarily in Europe.
Momondo is traditionally a strong player in its home markets in Scandinavia (it was born in Denmark).
Cheapflights was originally a travel deals business but switched to pureplay metasearch in 2015.
Momondo was bought by Cheapflights in 2011.
Hafner says Kayak is "looking forward to learning from them [Momondo] and sharing best practices as our brands expand globally".
Hugo Burge, CEO of Momondo Group for the past six years, after joining the company in 2000 to help scale the original Cheapflights business outside of the UK, praises the new mothership for its "proven track record of operating successful, customer-centric travel brands all over the world".
"We couldn't be more excited to join such an esteemed group of loved brands and join forces with Kayak to bring the best in meta search to our growing customer bases worldwide."
Still, the acquisition plays in front of the enormous backdrop of the Skyscanner sale to Ctrip from last year.
The $1.7 billion deal was seen by some as a coup and figurative stake-in-the-ground for the ambitions of the Chinese online travel agency giant.
Yet what it actually signified was how it and its friends at the Priceline Group (it had trousered a cool $700 million in investment from the US-based company) were cleverly positioning themselves as powerful players in the wider online travel landscape.
With Priceline Group owning Kayak and Momondo outright, plus Ctrip (with Priceline's money) controlling Skyscanner, there is very little left for rival group Expedia Inc to capture when it comes to travel search.
Where Expedia still has a march on the global Priceline-Ctrip behemoth is in hotels, with Trivago dominating in Europe and attempting to do the same in North America and Asia.