The latest figures from the Current Account Switch Service (CASS) show that the bank lost 18,022 and gained 1,880 customers between 1 July and 30 September 2018, equalling a net loss of 16,142.
It recorded a net loss of 16,641 between April and June, meaning during the middle six months of last year it suffered a net loss of nearly 33,000 customers through CASS.
However, TSB says customers can open accounts outside of the CASS and that 22,000 customers opened a bank account or switched to it between 1 July and 30 September 2018.
TSB’s IT disruption started on 20 April 2018 and saw many locked out of online banking and their mobile apps. In some cases, customers were even given access to other people’s accounts and in other cases, customers were stopped from switching to another bank. Wider problems continued throughout the summer.
The latest CASS figures also show that over 5.3 million bank switches have been completed using the official seven-day switching service since its launch in 2013, with over 900,000 switches in the last 12 months alone. Yet many more could benefit from switching.
See our Best Bank Accounts guide for top switching offers – including how to get cash or vouchers.