The chain owes more than £1bn and has reportedly hired financial advisors ahead of talks with creditors.
The group's most recent accounts show the chain's total debt was £1.12 billion at the end of past year - working out at £1.79 million a restaurant.
The company, which was bought by Chinese private equity firm Hony Capital in 2014, has to pay the first instalment of its repayments, worth £465 million in secured bonds, by August 2021.
'Final seen, had £1.6m of debt per restaurant.
A spokesperson from PizzaExpress told Hull Daily Mail: "We are not commenting on the speculation about PizzaExpress appointing creditors".
Pizza Express chief executive Jinlong Wang said: "Intense competition in the casual dining sector encourages innovation and we are constantly seeking ways to increase appeal to new and existing customers".
Pizza Express was founded in 1965 by Peter Boizot and it now has over 450 restaurants across the United Kingdom, and 100 more in Europe, Hong Kong, China and India.
"Unless they can get enough suitable deals informally with landlords and other creditors, then a Company Voluntary Arrangement, most recently used by Jamie's Italian, Prezzo and Byron Burger, may well be on the cards". Pizza Express is reportedly fighting to avoid going into administration.
This led to 94 closures and 500 job cuts.
Yep, the popular Italian chain, which brought dough balls to all of our hometowns, is at risk of becoming the latest high-street eatery to collapse.
Speaking about his restaurants shutting, Jamie said at the time: "I am deeply saddened by this outcome and would like to thank all of the staff and our suppliers who have put their hearts and souls into this business for over a decade".