Germany's Commerzbank has agreed to pay $1.45bn (£980m) to US authorities after it violated American sanctions against doing business in Iran and Sudan.
US regulators said Germany's second-biggest bank had "turned a blind eye" to illegal practices.
The fine also includes charges linked to money laundering on behalf of Japanese company Olympus.
Commerzbank chief executive Martin Blessing said the bank took the practices "very seriously".
The company would make "changes to our systems, training and personnel to address the deficiencies identified by US and New York authorities", Blessing said.
New York Department of Financial Services superintendent Benjamin M. Lawsky said Commerzbank staff had "sought to alter the Bank's transaction monitoring system so that it would create fewer 'red flag' alerts about potential misconduct [which] highlights a potential broader problem in the banking industry".
Commerzbank is just one of a number of big banks that have been charged for violating US sanctions, including BNP Paribas, Standard Chartered, HSBC and Credit Suisse.