Italian prosecutors want to indict the Bank of China’s Milan branch and almost 300 people over a money-laundering scheme.
Prosecutors in Florence allege €4.5bn ($5.1bn, £3.2bn) was transferred from Italy to China.
It was earned through prostitution, counterfeiting, tax evasion and labour exploitation, they say.
The Ansa agency said (in Italian) that four senior managers with the Bank of China could be indicted.
Close to half the €4.5bn, transferred between 2007 and 2010, went through the bank’s branch in Milan, investigators say.
The Bank of China received €758,000 in commission for the transfers, it is claimed.
There were millions of transactions, Ansa said, that were below the €2,000 threshold that would have triggered money-laundering checks.
That threshold has since dropped to €1,000.
A judge will now decide whether the Bank of China and 297 individuals will face trial.
Neither the bank nor the Chinese government has yet responded.
“The maxi-laundering strengthened the economic capacity of the Chinese mafia organisations devoted to illegal immigration from their country,” said Ansa.
In December 2013, a spotlight was thrown on working conditions for Chinese migrants in Italy when seven workers died in a fire at a garment shop in Prato, near Florence.
Some factories were linked to Chinese organised crime, Tuscany’s regional governor said.