Britain's part-nationalised banks, Lloyds Banking Group and Royal Bank of Scotland, are expected to report combined losses of at least £4 billion for last year.
Significant losses will revive fears that taxpayers will have to wait several years before recouping the £66 billion pumped into the banks by the Government at the height of the financial crisis.
RBS is expected to reveal losses of up to £2 billion while Lloyds could unveil a deficit of around £3.5 billion, after compensation from mis-selling payment protection insurance (PPI) is deducted, The Sunday Times said.
The banks have had a turbulent year, with the country's economic downturn and the ongoing eurozone debt crisis hitting performance, as well as the ongoing bonus furore.
Lloyds, which is 41% owned by the taxpayer, received £20 billion from the Government, while RBS, which is 83% state-owned, received £45 billion.
While there has been some recovery in the share price in the last couple of months, both banks are close to 50% lower than they were a year ago, amounting to a paper loss of more than £30 billion for the Government.
Poor results will also fuel the debate over bankers' pay, which has been raging in recent weeks.
RBS has been at the centre of the row, which ultimately led to chief executive Stephen Hester waiving his £963,000 all-shares bonus.
However, Mr Hester is reportedly still in line to receive shares worth about £660,000 that were awarded as part of the £2 million bonus he was handed for his 2010 performance.
Lloyds has managed to avoid the bonus row so far after boss Antonio Horta-Osorio waived his annual payout due to a leave of absence.
Mr Horta-Osorio, who returned to work last month after taking two months off due to severe sleep problems, said he acknowledged that his absence had had an impact both "inside and outside the bank, including for shareholders".
Both bosses are likely to focus on what progress they are making towards delivering a better return to the taxpayer.
RBS has moved to strip down its investment arm Global Banking and Markets (GBM) amid increased Government pressure to focus its operations on UK high street services.
GBM, which employs 18,900 people worldwide, deals with a range of financial services such as debt advice, equity trading and mergers and acquisitions.
The restructuring will lead to around 3,500 job losses, on top of the 2,000 announced by the bank last summer.
The move was largely welcomed by investors, with shares up around 40% since the start of this year.
Lloyds is close to selling off 632 branches, a move enforced by the EU as a condition of taking a state bailout, after naming the Co-operative Bank as a preferred bidder.
The bank also announced 15,000 job cuts last summer as it closes or sells down assets across the UK and overseas.Suggest a correction