HSBC's Mexican unit was hit with a record $27.5m fine for failing to comply with local rules to flag suspicious transactions and promptly report potential money laundering cases.

Grupo Financiero HSBC said that it paid the fine to the Mexican regulator, the National Banking and Securities Commission, for failing to quickly report 1,729 unusual transactions. The bank didn't flag a further 39 unusual transactions and 21 administrative failures. The fine represents the biggest sanction that the Mexican regulator has ever imposed on a bank and accounts for over half of HSBC Mexico's 2011 net profit.