Pizza Express is considering closing 15% of its UK restaurants, which would mean the loss of 1,100 jobs.
The chain is the latest High Street outlet to undertake a restructuring of its business after trading was halted by the coronavirus pandemic.
It is poised to launch a Company Voluntary Arrangement deal in the near future, which could mean 67 of its 449 outlets will close.
But it said the final outcome of the restructuring has «yet to be decided».
A spokesman told the BBC the company could yet say which outlets were being considered for closure.
Previously, Pizza Express has said the majority of its restaurants are profitable.
The company closed all its UK restaurants on 23 March after the government-mandated lockdown.
Restaurants were allowed to reopen in July. Pizza Express opened 60 initially and said in Tuesday’s statement that customer demand had been «encouraging» at these.
It now has 166 outlets open as the Eat Out to Help Out initiative starts, and says plans for further re-openings are well underway.
The company said the restructuring would put the business on a stronger financial footing in the new socially distanced environment.
Pizza Express has heavy debts and last year was known to have started talks to put its debts of more than £1bn on more favourable terms.
A brief history of Pizza Express
1965: Pizza Express founder, the late Peter Boizot, brought a pizza oven from Napoli and a chef from Sicily to open his first restaurant in London’s Soho.
1992: Mr Boizot grew his empire over the following almost-three decades before selling it for £15m to Hugh Osmond and Luke Johnson, the man who was – until recently – chairman of Patisserie Valerie. They floated it on the stock market the next year and ultimately sold out in 1997 when it was worth £150m.
2003: It was taken private again in a £278m deal by two private equity firms who then floated it two years later – although it lasted less than a year on the public markets before it was returned to private equity hands.
2014: It changed hands again, this time to be acquired for £900m by its current owner, Chinese private equity house Hony Capital.
2020: It has more than 600 restaurants globally: 454 in the UK; 19 in Ireland; 24 in Hong Kong; 6 in Singapore; 14 in UAE; 60 in China; and 49 other international sites operated by franchisees.
Andy Pellington, group chief finance officer, said in a statement: «While we have had to make some very difficult decisions, none of which has been taken lightly, we are confident in the actions being taken to reduce the level of debt, create a more focused business and improve the operational performance, all of which puts us in a much stronger position.»