A malfunction in Toss Bank's internal transfer system wrongly credited about 32.5 billion won ($22.6 million) to customer accounts, the online lender said. Toss Bank has recovered roughly 80% of the amount and is working to retrieve the rest.
The internet-only bank disclosed the incident as a financial accident on the 22nd.
According to the filing, the error occurred at around 2:20 p.m. on the 7th during an update to Toss Bank's internal transfer system. As a result, some transfers sent to Toss Bank from other financial institutions failed in practice but were recorded in customer accounts as if they had been completed. The problem came to light through customer inquiries about irregular deposit processing on interbank transfers.
The total amount involved was 32,493,696,000 won. Of that, 25,205,653,000 won has been recovered so far, while recovery procedures are under way for the remaining 7,288,043,000 won. The final estimated loss has yet to be determined.
No funds were actually withdrawn from accounts at other financial institutions, however, and neither senders nor recipients suffered direct monetary losses, the bank said. Toss Bank said it restored the system immediately after the error and that all transfers are now processing normally.
Toss Bank posted a notice of the error on its website the same day and, starting on the 12th after the Chuseok holiday, has been notifying affected customers in stages and correcting the transactions.
The bank has also put follow-up measures in place to address customer inconvenience and prevent a recurrence. Since the 12th, Toss Bank has operated a dedicated hotline and added call center staff. It has formed a task force including the chief consumer protection officer and the chief technology officer to monitor the progress of corrections and customer complaints.
The bank also launched an IT internal control task force led by the chief executive. IT executives and working-level staff, along with the human resources, organizational culture and compliance units, will review system operations and internal controls overall and draw up improvement plans.
"We bow our heads in apology to our customers," Toss Bank said. "We will approach the resolution with a sense of responsibility so that we can become a bank our customers trust."