The government has started the process of selling more student loan debt to the private financial sector. It has announced that loans made to students in England between 2002 and 2006 will be put up for sale - to be followed by other pre-2012 loans - with the aim of raising £12bn.
Universities Minister Jo Johnson said the sale would have "no impact on people with student loans".
But the National Union of Students said it was an "ugly move on students".
The government has had a long-standing aim of selling off the student loan book to private investors - with types of loans being sold in separate stages.
Over the next four years it aims to dispose of the loans from before 2012, when tuition fees in England were trebled to £9,000 per year. The slice of loans now being put on sale - dating from 2002 to 2006 - have a face value of £4bn.
The government is promising that there will be "no changes to the terms and conditions" for borrowers - so that rates of repayment for former students will remain the same. It means that interest on these student loans will become an income for private investors, but repayments will continue to be collected through taxation and the Student Loans Company.
The Intergenerational Foundation think tank has calculated that a student borrowing for three years' tuition could pay back £54,000 - before debts are cancelled after 30 years.
The Universities Minister Jo Johnson says the sale of assets is part of the drive to bring "public finances under control".
But he said it would "only proceed once we are satisfied that it represents value for money for the taxpayer".
