This could get messy. IT giant IBM claims the Priceline Group has refused to negotiate a license to use four of its patents.
In a complaint filed at the US District Court in Delaware this week, IBM says Priceline Group and its subsidiaries such as Kayak and Opentable should be barred from using the patents without authorisation and pay damages for infringement.
The patents relate to a system which presents applications and advertising in an interactive platform, sign-on tools and methods for storing user information from previous browsing behaviour.
This isn't a new row between the pair - IBM claims it notified Priceline Group in 2011 that it was infringing the patents.
The filing says:

"Priceline has refused to engage in any meaningful discussion on the merits, resorting instead to delay and non-responsive answers."
Priceline Group officials did immediately not return requests for a response (and have so far declined to comment to other media outlets).
Details for three of the patents are available here, here and here.
IBM currently has around 80,000 patents filed in the US - adding 7,500 in 2014, more than any other company and a feat unsurpassed by any other company for more than 20 years in a row.
Here is the filing:
NB:Patent image via Shutterstock.