Shares of Standard Chartered bank have tumbled despite the bank denying allegations that it illegally "schemed" with Iran to launder money.
Shares fell 15% in early London trade, after falling 16% in Hong Kong.
The New York State Department of Financial Services said the UK-based bank laundered as much as $250bn (£161bn) over nearly a decade.
It said the bank hid transactions for "Iranian financial institutions" that were subject to US economic sanctions.
The regulator said that Standard Chartered had hidden 60,000 such secret transactions.
However, the bank denied the allegations, saying that it "strongly rejects the position or portrayal of facts as set out in the order" issued by the regulator.