Novus Leisure has acquired three Rocket restaurant sites for an undisclosed sum.
The deal with 3Sixty Restaurants' chief executive James Horler is expected to complete on 30 January 2017.
Horler will keep the Nottingham Rocket site, which will join the 14-strong Ego Restaurants group.
The three London sites being taken on by Novus Leisure include Canary Wharf, Adam's Court and Bishopsgate.
Rocket restaurants' menu includes combination salads such as chicken Milanese, fish and chip salad and surf and turf salad, alongside pizzas and seasonal dishes.
It is not yet known whether the sites will be rebranded into Novus Leisure's current restaurant and bar brands which include Balls Brothers and Tiger Tiger.
Novus Leisure chief executive Toby Smith said: "We are delighted to add the three Rocket sites to our unrivalled London portfolio, not only will this acquisition strengthen our estate in the City of London, it will also create an exciting opportunity to operate in Canary Wharf for the first time in the Company's history. We are looking forward to welcoming the Rocket team into the Novus family."
Commenting on the sale, James Horler, CEO, 3Sixty Restaurants Ltd added: "The sale of Rocket to Novus makes a lot of sense. We are very focused on an organic self-funded growth of Ego in pubs throughout the regions and have opened six sites already with another two in the immediate pipeline. This will take the Ego estate to fifteen."