Panama Papers: FCA asks firms to check for links
The UK's Financial Conduct Authority (FCA) has given 20 banks a deadline of 15 April to check if they have links to Mossack Fonseca, the firm at the centre of the Panama Papers scandal.
Papers leaked from the law firm detailed how the world's rich and powerful used it to shield money from taxation in their home countries.
The FCA said it had written to the firms earlier this week.
Banking giants, including HSBC, deny they help clients to avoid tax.
HSBC, Credit Suisse and the Royal Bank of Scotland-owned Coutts Trustees all feature in the leaked Panama Papers.
The revelations in the papers are based on more than 11 million documents from Panama-based law firm Mossack Fonseca.
They name lenders said to have helped to set up structures making it hard for tax officials to pinpoint money flows.
They also name institutions alleged to have helped firms that were subject to international sanctions.
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In a statement, the FCA said: "The FCA has written to a number of firms about this issue, including those on our Systematic Anti-Money Laundering Programme, and we are working closely with a number of other agencies who are also looking at this.
"As part of our responsibility to ensure the integrity of the UK financial markets we require all authorised firms to have systems and controls in place to mitigate the risk that they might be used to commit financial crime."