The Bank of China is facing a daily fine in the US if it does not comply with a court request to give details of customers accused of selling fake goods.
The state-owned lender was held in contempt of court in Manhattan last week for refusing to turn over the records.
The bank is appealing the civil contempt order and fine of $50,000 a day starting on December 8.
The BOC said it would be violating China’s privacy law if it gave the information.
The records stem from a 2010 lawsuit by a group of luxury retailers including Gucci and Yves Saint Laurent that sued a group of Chinese companies for allegedly selling counterfeits goods like handbags.
The luxury brands had asked US district judge Richard Sullivan to order the BOC to pay $12 million to cover their losses from counterfeiting or impose a fine.
The judge had initially ordered the BOC to provide the customer information in 2011 and then renewed the order in September.
“BOC’s refusal to comply with US law, while it continues to receive the benefits attendant to its banking activity in the US, has inflicted a significant harm on plaintiffs and the general public,” Richard Sullivan said.
“Only a large fine will have a coercive effect on BOC at this stage.”
He has also ordered the top-four Chinese lender to cover the retailers’ legal costs.
But the BOC said the judge lacked the jurisdiction to force its compliance.
The BOC is China’s fourth biggest lender by assets and made a profit of nearly $28 billion in 2014.