The U.K. arm of Santander was fined approximately 107.8 million pounds (U.S. $132 million) by the country’s financial services regulator for “serious and persistent” gaps in its anti-money laundering (AML) controls.

Between December 2012 and October 2017, the accounts of more than 560,000 business customers were not checked properly due to repeated failings in Santander UK’s AML systems, the Financial Conduct Authority (FCA) said in a press release Friday.

Across six cases examined by the regulator, approximately £298 million (U.S. $366 million) of suspect funds were transferred in and out of business accounts before they were closed without triggering any warnings or requiring enhanced checks.

The FCA found Santander had ineffective systems to adequately verify customer information about the type of business they would be doing or the size and frequency of transactions. The bank also failed to monitor the amounts customers said would be going through their accounts compared to the sums that did.

For example, one new customer opened an account as a small translations company with expected monthly deposits of £5,000 (U.S. $6,100). Within just six months, the account was receiving millions in deposits and moving the cash quickly to other accounts, the FCA detailed.

In March 2014, Santander’s AML team flagged the suspect account and recommended it should be closed. But because of a mix of poor processes and structures, its recommendation was not acted upon until September 2015, the FCA said. As a result, millions of pounds continued to be transferred in and out of the account with no other actions being triggered.

When Santander in September 2015 agreed to keep the account open following a request from law enforcement, the bank failed to keep track of the request or monitor the account despite the known risks. The account remained open until the FCA wrote to Santander in December 2016, by which time around £269 million (U.S. $330 million) had flowed through it.

Five other customers accounted for a further £29 million (U.S. $36 million) worth of suspect funds. The FCA’s decision notice said Santander was not aware of these companies being money service businesses at the time of onboarding them, and when the bank did become aware, it failed to act appropriately and carried on with business as usual.

Santander was aware there were significant weaknesses in its AML systems and controls and began to make improvements in 2013. When the bank in 2017 deemed these efforts inadequate, it implemented a comprehensive restructuring of its processes and systems, the FCA said. The bank continues to invest in its remediation program.

Santander did not dispute the FCA’s findings and agreed to settle, qualifying it for a 30 percent discount on a financial penalty of approximately £154 million (U.S. $189 million).

Santander did not respond to a request for comment.

“Santander’s poor management of their anti-money laundering systems and their inadequate attempts to address the problems created a prolonged and severe risk of money laundering and financial crime,” said Mark Steward, the FCA’s executive director of enforcement and market oversight, in a statement. He warned the FCA will “continue to take action against firms which fail to operate proper anti-money laundering controls.”