While the big guns of online travel compete over what brand can spend the most on digital ads, developments are still allowed to continue for everyone else.
InternetHotels Sister site HotelsAtAnywhere was part of the acquisition but will redirect to HotelPlanner.
The two sites were launched in 1998. CEO of the pair, Paul Simon, will join HotelPlanner in its business development division.
The acquisition comes less than a year after HotelPlanner bought booking site Hotel Hotline, also for an undisclosed fee – a move that included its eventual closure and domain sold to a British ex-High Street travel agency known as Ace Hotels.
Founded in 2002, HotelPlanner has offices in London, Hong Kong, West Palm Beach, and Las Vegas.
It has a niche in offering hotel procurement for sports teams and also owns Meetings.com, which offers services around hotel stays.