Byron will permanently close 31 restaurants with the loss of 651 jobs despite the burger chain being bought out of administration.
It will shut more than half its 51 sites after becoming the latest casual dining business to be hammered by the coronavirus pandemic.
Administrators at KPMG said that the brand and certain assets had been sold to a newly formed company called Calveton in a move that will protect its 20 remaining sites and 551 employees.
Will Wright, partner at KPMG and joint administrator, said the sale “ensures Byron will continue to have a presence on our high streets”.
Meanwhile, sushi chain Itsu will close two sites and cut rents on 53 of its 77 outlets in a restructuring to shore up its finances following months of closure.
Itsu said a combination of “zero trade and ongoing social distancing” means trading will be significantly affected this year and next.
The group, which is run by Julian Metcalfe who co-founded Pret A Manger, said it will seek to protect as many jobs as possible and does not anticipate large scale redundancies. Itsu employs 1,115 people.
It comes after Itsu hired restructuring experts AlixPartners to explore options for the business earlier in July.
The proposals, which will require the approval of landlords, are part of a company voluntary arrangement (CVA) – an insolvency procedure deployed by firms as a way of staving off collapse. A string of food chains have pursued similar restructuring deals since the crisis hit.