They have yet to opt in to the official review, with the FCA warning that time is running out, the Daily Mail reports.
Banks’ redress payments to customers embroiled in the interest rate swap mis-selling scandal surged to £158.6m in December, paid out to just over 1,000 firms, putting most banks on track to reach their projected review targets.
Figures released by the FCA showed that Barclays, Lloyds and the Royal Bank of Scotland all surpassed their set targets for determining redress for reviewed cases in December, while HSBC lagged behind its initial projection by one percentage point.
Yet 3,700 of the 18,700 companies invited to join the review have yet to respond to letters sent by banks.
The FCA has set a deadline of the end of May for the banks to send out letters of redress to all businesses mis-sold a swap. The review will be closed to new entrants after the deadline.
An FCA spokesman said: “We would encourage the 3,700 firms yet to respond to do so as quickly as possible.”