Pub group Mitchells & Butlers says it is examining raising money from investors because it is unclear how long current restrictions will last.
Each month closed loses the business up to £40m, plus it has to meet £50m debt costs each quarter.
“The directors believe it is prudent to explore an equity capital raise,” M&B said.
It added that it had not yet made a decision about the timing, size, or terms of the fund raising.
“With no sites trading, ongoing monthly cash burn is approximately £35m to £40m,” it said.
On top of that it has to meet the next quarterly payment date for debt service of £50m on 15 March.
All pubs in England are now closed until late-February at the earliest under the latest lockdown.
“The future facing the hospitality sector remains extremely uncertain,” M&B said.
M&B operates about 1,700 pubs across the UK, including brands such as All Bar One, Nicholson’s and O’Neill’s.
The company said trading in the three months to 2 January, which included the November lockdown in England and the Christmas period, was 67% below 2019’s levels.
For the pubs that were able to trade, sales were 30% lower than the same period last year.
“There is a real and pressing need for support for businesses if we are to return to being the vibrant sector and important employers that we were,” said chief executive Phil Urban.
“Mitchells & Butlers was a high-performing business going into the pandemic and with the support of our main stakeholders, I have every confidence that we can emerge in a strong competitive position once the current restrictions on us are lifted.”
Finance firms at risk
Separately, the City watchdog has warned that some 4,000 financial services firms were at a “heightened” risk of collapse due to the pandemic even before the second wave struck.
The Financial Conduct Authority (FCA) said its survey of 23,000 firms found that at the end of October 17% of those with low financial resilience faced a greater risk of failure.
Around 30% of the firms, which were mainly small businesses, had the potential to cause harm if they went bust, the FCA warned.
The poll was done to check on the resilience of financial services firms to the coronavirus crisis.