As part of the agreement, William Hill is investing £80m in the takeover and a further £10m in equity. SkyBet is contributing £20m.
OpenBet is a sports betting and gaming technology provider, which has been a William Hill supplier since 2008.
William Hill said it had agreed a 10-year commercial agreement with NYX, with the aim of it becoming the “industry’s leading supplier of omni-channel betting and gaming technology and content”.
Read more: Sky offloads betting business for £800m
Matt Davey, chief executive of NYX Gaming Gaming Group, said: “To have a consortium of operators with the pedigree of William Hill and Skybet and the public support of Paddy Power Betfair highlights the strength of NYX’s proposition and I look forward to extending our relationship with them."
William Hill chief executive James Henderson said: “Our new commercial agreement is a key step in delivering our technology strategy by enhancing our current platforms and, in parallel, developing a new back-end platform for William Hill to complement and support our Trafalgar platform which is focused on our front-end user experience."