The UK's largest care home provider, which bought many of the Southern Cross properties, has said it is in talks to raise money to pay its debts.
Four Seasons must pay back £780m of debt this September but has said it is unlikely to be able to raise that much again from lenders.
Instead it has entered talks with investors to try to attract new investment of up to £250m.
The GMB union has warned the company may face ongoing financial difficulty.
The group looks after 20,000 people and employs 30,000 staff across around 500 properties.
"We warned back in the autumn [when Southern Cross was sold] that there was a great risk that residents and staff were jumping from the frying pan into the fire," the GMB's Justin Bowden told the BBC.
However the company has said that its negotiations with potential investors, including its existing shareholders, are progressing well.
"I am not absolutely confident that I will get the full amount of debt," from lenders and capital markets, Four Seasons chief executive Peter Calveley told the BBC.
"If there is an equity gap because we cannot refinance, we're speaking to our shareholders and also to third-party equity providers, to bridge any gap [between what the firm can borrow and what it needs to pay back]."
Four Seasons may call on existing investors, including the state-owned Royal Bank of Scotland, to increase its stake, potentially leaving the taxpayer with majority-ownership of the UK's largest care home group.
It hopes to have a deal agreed by March and concluded by the summer.
However, Mr Calveley says, even if the financial markets deteriorate, the firm will not close any homes.
"We've had much more debt than this before, and we carried on operating successfully through that," he said.
Four Seasons incurred around £1.4bn of relatively short-term debt when it was bought by the Qatar Investment Authority in 2006, which borrowed the money to finance the deal.
Following the financial crisis, the firm was unable to borrow money again in order to pay back - or re-finance - existing debts.
Instead lenders, including the Royal Bank of Scotland, took ownership of the group in exchange for writing off £780m - or roughly half - of the debt it owed.
In 2010 the group faced another deadline to pay back its remaining debts, which was then extended to September 2012, the deadline the group must now meet.
"Four Seasons are on a treadmill of debt, continually refinancing, taking on more debt and paying out tens of millions of pounds in fees to advisers. How long can this carry on until their debt bubble bursts?" said the GMB's Mr Bowden.
Despite its significant debts and restructurings, Fours Seasons has been expanding successfully over the past two years to increase earnings.
In addition to taking on around 140 Southern Cross homes, in addition to the 40 it already owned, the firm also bought mental health group Care Principles from Barclays Capital.
The group, owned by a holding company registered in Guernsey, has said it increased capacity by 40% in 2011 and that the new properties have already boosted profits.
Because of its offshore ownership, Four Seasons does not have to publish full and up-to-date accounts, but recently made available its accounts for the period to the end of December 2010, reporting a pre-tax profit of £27.8m.
Four Seasons also has a division registered in the Cayman Islands.
However, in a statement, the firm said it had received no tax benefit from its offshore structure in recent years.
Whilst the company has struggled from falling local authority revenues and rising costs, health industry analysts say it is in a very different position to Southern Cross and may attract investment.
"The long-term prospects of this market are pretty good, an ageing population, a population of which there are people who are mentally ill, in two or three years time there won't be the same pressure on public funding," said William Laing from analysts Laing and Buisson.
The firm's management is well respected, he said, and unlike Southern Cross, it owns a number of its own properties.
"No-ones going to pull the rug, because they don't have the problem with private landlords," he Mr Laing added.
"Occupancy has risen, quality has risen, investment year-on-year has gone up, and profitability has risen," said chief executive Mr Calveley.
"The only thing that gives these homes significant value is the operations within them. Whatever happens, whether it's our shareholders, our lenders, they understand the value of the business," he added.