Hilton (HLT), InterContinental Hotels Group (IHG), and Marriott International (MAR) are under investigation by the UK Competition and Markets Authority over suspected sharing of sensitive commercial information through the hotel analytics platform STR, owned by CoStar Group (CSGP), the regulator said Monday.

CoStar is also facing the investigation, according to the CMA.

"When rival businesses share competitively sensitive information -- including through a third-party data analytics provider -- this reduces the uncertainty competing businesses normally have about how each other will act," the CMA said. "This can affect how strongly companies compete because it makes it easier for them to predict what each other will do and coordinate their behavior."

Hilton, InterContinental, Marriott and CoStar didn't immediately respond to MT Newswires' requests for comment.