The owner of some of the UK's biggest shopping centres, Intu, has said there are doubts that it can survive unless it raises extra funds.
Its comments came as the firm - which owns Manchester's Trafford Centre and the Lakeside complex in Essex - reported a £2bn loss in 2019.
The weakness in the retail sector meant Intu wrote down the value of its shopping centre sites by nearly £2bn.
Intu will try to raise extra cash after an earlier plan to raise £1bn failed.
The collapse and contraction of High Street retailers has left landlords such as Intu struggling to fill vacant space. At the same time, Intu has run up debts of nearly £5bn.
In January, the firm approached its shareholders to ask for more money amid the downturn in the retail sector.
But last week, Intu said it was at risk of breaching debt covenants after it was forced to abandon the fundraising attempt. It said "extreme market conditions" deterred investors from giving fresh cash.
To help it keep going, the firm said it would try to engage with investors, or it might have to sell more of its assets.
The company has already been selling shopping centres to raise cash.
Intu said it could also try to seek waivers on its debt commitments to lenders and spend less in the short term.
Intu's UK shopping centres
Eldon Square, Newcastle
Merry Hill, West Midlands
Trafford Centre, Manchester
Victoria Centre, Nottingham
Centres run as joint ventures:
St David's, Cardiff
The Mall, Cribbs Causeway
Last year was the "worst" for retail sales in 25 years, trade body the British Retail Consortium said in January.
Tough trading conditions in 2019 hurt landlords, who struggled to fill vacant stores.
Firms such as Debenhams, Toys R Us, House of Fraser, New Look and HMV all tried to negotiate with landlords to reduce rent.
Intu was hit by some of the most high-profile retail failures, as more firms shut up shop after more online competition and problems paying business rates and increased wages.
The firm's share price has collapsed since its high of 378p in December 2010.
Its shares stood at 34p when trading began at the start of 2020, and on Wednesday were worth about 4.7p after falling 17% in reaction to its results.