By Georgie Keate
Shares in Standard Chartered took a dive today after the US charged the bank with money laundering with Iran.
The bank's shares fell almost 20% in London and 16.6% in Hong Kong.
Standard Chartered says it '"strongly rejects" claims by the New York State Department of Financial Services that the bank has plotted to launder $250 billion (£160 billion) with the Iranian government, hiding transactions to avoid sanctions.
The US financial system has argued the bank's actions left America "vulnerable to terrorists" and labelled them a "rogue institution".
The allegations state Standard Chartered worked with Iranian clients to strip information "from wire transfer messages used to identify sanctioned countries, individuals and entities" and re-route nearly 60,000 US payments through the bank's branch in New York.
A bank employee is even quoted as saying: "You f***ing Americans. Who are you to tell us, the rest of the world, that we're not going to deal with Iranians."
Standard Chartered protested their innocence in a statement saying "well over 99.9%" of its transactions with Iran have met the terms of international regulations. The 0.1% however amounts to £14 million.
The bank has been threatened with expulsion from New York and will be summoned to the city on August 15th to explain the transactions and convince regulators that their license "should not be revoked".
The bank has also been charged with a '"staggering cover up" of its actions dating as far back as 1995 when Standard Chartered lawyers began advising it on how to get around US sanctions.
The scandal comes just a week after the bank's chief executive, Peter Sands, described his company as "boring" in comparison with others in the spotlight for misdemeanours.