Turkey's state-controlled Halkbank asked the US Supreme Court to throw out a lower court ruling saying it could be prosecuted on criminal charges it helped Iran evade American sanctions.
In a petition posted this week on the Supreme Court's website, Halkbank said it was entitled to "absolute immunity" under the common law because the sovereign immunity that countries have extends to their instrumentalities.
Halkbank pleaded not guilty to fraud, money laundering and conspiracy charges over its alleged use of money servicers and front companies in Iran, Turkey and the United Arab Emirates to evade sanctions.
Prosecutors said Halkbank helped Iran secretly transfer $20 billion of restricted funds, and helped launder money through the US financial system.
In October, the federal appeals court in Manhattan decided that Halkbank could be prosecuted.