MAS imposed penalties of S$2.6 million ($1.93 million) for DBS, S$600,000 for OCBC, or Oversea-Chinese Banking Corp, S$400,000 for Citibank and S$200,000 for Swiss Life.
Asked whether illicit activities had taken place involving the institutions, MAS said its checks focused on compliance with its requirements.
DBS failed to adequately inquire into the background and purpose of "unusually large transactions", it said.
A Swiss Life spokesperson said it had terminated a client relationship in 2020 after being approached by authorities about a contract.
"Since then, and in close cooperation with the authorities, additional measures have been implemented within Swiss Life (Singapore) to detect client misconduct more effectively."
Persons:
Wirecard, OCBC, Chen Lin, Yantoultra, Selina Li, Martin Petty, Conor Humphries
Organizations:
Citibank, DBS, Swiss, Monetary Authority of Singapore, Chinese Banking Corp, MAS, FIs, Singapore police, Thomson
Locations:
SINGAPORE, Singapore