Two former Bank of China managers have been charged in the US with stealing $485m (£272m) and attempting to launder the money through Las Vegas casinos.
The bankers are accused of setting up fake firms to launder the money
Xu Chaofan, Xu Guojun and their wives were charged with 15 counts of racketeering, money laundering and fraud, the US Justice Department said.
The two men tried to launder the Bank of China's money through Hong Kong, Canada and the US, the department said.
The alleged scam, which ran from the early 1990s, was uncovered in 2004.
Authorities in the US said the fraud scheme also involved the brother-in-law of one of the bankers, Kuang Wa Po, who is currently described as a fugitive.
A sixth man, Yu Zhendong, was detained but later sent back to China to face racketeering charges after agreeing to cooperate with the investigation.
Assistant Attorney General Alice Fisher and Nevada US Attorney Daniel Bogden said that the two Bank of China managers set up shell corporations in Hong Kong and moved the bank's money into fake firms and personal accounts.
"The indictment charges the defendants with laundering a significant amount of the stolen money through Las Vegas casino accounts," they said.
The two men later attempted to emigrate to the US from China with their wives by obtaining false identities and entering into sham marriages with naturalized US citizens, the Justice Department said.
The two couples and their accomplices were detained by US authorities in 2004, the department said.
State-owned Bank of China is one of China's leading commercial banks.