Authorities raided the Buenos Aires offices of British bank HSBC on Wednesday investigating alleged tax evasion involving more than 4,000 influential locals' Swiss accounts, a court source said.
About 100 agents took part in the raid, the source said, adding the bank gave "court authorities the documents that are available and is in the process of additional steps."
In November, Argentina's tax agency, AFIP, charged HSBC with helping 4,040 Argentines avoid paying taxes by stashing money in secret Swiss accounts on their behalf.
HSBC at the time said in a statement that it "emphatically rejects (the charges) of participation in any illicit association, including any organization allowing the transfer of capital in order to evade taxes."
Wednesday, it said it is working with Argentine regulators and authorities and will continue to do so.
The charges are the latest woes for the banking giant, after ex-employee Herve Falciani leaked data to French authorities on thousands of HSBC customers, saying he wanted to expose tax fraud.
The leak sent shockwaves through the world of Swiss banking, long valued by wealthy individuals for its stability and traditions of banking secrecy, and led to a French probe into HSBC to determine whether it had also helped French customers avoid taxes.