The internet venture will combine 365's digital sports content and products, including Football365, Planet Rugby, Cricket365 and Planet-F1, with Chrysalis's internet content business Rivals.
Each firm will appoint two non-executive directors to the board of the venture.
More than two million users a month visit 365's websites, while the Rivals network has more than a million users each month.
Richard Pembroke, currently managing director of 365's internet division, will become managing director of Newco, and Marcus Leaver, presently chief executive of Rivals.net, non-executive chairman.
