Dutch bank ING Groep will pay €775m in a settlement with prosecutors, who accused its financial controls of being so poor that customers were able to easily launder money.
The settlement, one of the largest ever struck with Dutch financial crime prosecutors, covers a period from 2010 to 2016.
ING is the third European bank to be hit by money laundering allegations this year, with Denmark's Danske Bank facing ongoing investigations and problems that led to the failure of Latvia's ABLV.
Prosecutors said they had launched their investigation in 2016 after realising that a pattern of violations was a signal of deeper underlying problems.
They found ING violated Dutch law on preventing money laundering and financing terrorism "structurally and for years" by not properly vetting who were the beneficial owners of client accounts and by not noticing unusual transactions through them.
"The result was that clients for years were able to make use of ING bank accounts for criminal activities pretty much undisturbed," a prosecution statement said today.
It cited four specific examples where ING accounts were used for crime, most notably for bribes paid by telecommunications company VEON, formerly known as VimpelCom, in Uzbekistan.
VEON settled US and Dutch charges for $835m in 2016.
"ING should have seen that the money streams that ran through those bank accounts possibly were coming from crime," prosecutors said.
Of the settlement, €675m was intended as a fine and €100m as the return of ill-gotten gains, they added.
ING first disclosed it was the target of a criminal investigation in a note to its 2016 annual report and said it could face "significant" penalties.
It had not taken a provision ahead of the case, and will book the fine in the third quarter, it said.
ING said it deeply regretted its failures. "Not meeting the required standards is unacceptable and ING takes full responsibility," it said in a statement.
"Even though our policies and procedures in the Netherlands resulted in us terminating the relationships with thousands of clients, it was not enough," it added.
The bank said its executive board, headed by CEO Ralph Hamers, had agreed to forgo a bonus for 2018.
ING agreed in 2012 to pay a penalty of $619m for illegally facilitating billions of dollars worth of payments through the US banking system on behalf of Cuban and Iranian clients, in violation of American sanctions.