The report criticises the Tory–Liberal Democrat Coalition's handling of the state-owned banks. It says the state of the financial sector could mean few likely buyers for RBS and Lloyds.
The UK Government still owns more than 80% of RBS and 40% of Lloyds. Ministers eventually want to return the banks to private ownership, but MPs warn they face an uphill task.
The reports looked at the handling of Northern Rock, sold last year at an estimated £2 billion loss to the taxpayer. Only two bidders vied to take it over the bank, MPs noted.
Margaret Hodge, who chairs the Public Accounts Committee, said: "The lack of competition does not fill us with confidence that the taxpayer will make a profit on the sale of the two banks which remain in public ownership, RBS and Lloyds. There is a risk that the £66bn invested in RBS and Lloyds may never be recovered."
In a warning to the Treasury, she said it was vital final decisions on the banks are made with "value to the taxpayer taking precedence over speed of exit".
Some MPs say the Coalition should buy the part of RBS it does not own already.
They argue this would let the UK Government force the bank to increase lending to small businesses, a key problem for the economy. But ministers are understood not to have been persuaded by that argument.
Today's report warns Treasury officials were slow to nationalise Northern Rock, which made losses difficult to avoid.
Ministers "spent five months trying to find a private-sector buyer before giving up", said Mrs Hodge, adding that once the bank was nationalised the UK Government "failed to effectively challenge the optimistic business plan put forward by the bank's management to split the bank".
The run on deposits at Northern Rock in September 2007 was a pivotal moment in the financial crash. After nationalisation, the bank was split into Northern Rock plc and Northern Rock (Asset Management), which held its bad debt.
The move was supposed to generate lending but it fell well short of its £15bn target, reaching just £9.1bn.
Earlier this year the Treasury's most senior official, Sir Nicholas Macpherson, admitted the taxpayer lost out because of five months of "drift" as the crisis unfolded.
The Treasury has accepted its part in a "monumental collective failure", the report says.
Richard Bacon, MP for South Norfolk and a member of the committee, said: "With better regulation this mess could have been avoided, but at least Northern Rock has now returned to the private sector. However, this report is a reminder that the civil service is short of skills and experience from the world outside Whitehall."
A spokesman for Scottish Finance Secretary John Swinney said: "This report will only serve to remind people of the catastrophic failure of banking and financial services regulation which happened on the watch of the UK Labour Government when Alistair Darling, the man leading the No [to independence] campaign, was chancellor."