UK banks have paid out £159m in redress for interest rate swap misselling claims by December, the latest FCA figures show.
Last year the banks were ordered to review past interest rate swap business with 18,700 customers now part of the review.
Just 1040 people have received redress while 672 have not been given redress. There are a further 7,500 customers in the redress phases.
The banks have agreed to offer customers 8 per cent simple interest on top of redress payments to compensate for the cost of being deprived of their money.
The Royal Bank of Scotland has the most sales reviews to deal with tackling more than 9,000 cases.
Lloyds Banking Group is reviewing nearly 2,000 sales while Barclays and HSBC have around 3,000 cases each.