Swiss bank UBS has been fined £29.7 million by the City watchdog for failings which allowed convicted rogue trader Kweku Adoboli to lose £1.4 billion.
The Financial Services Authority (FSA) said procedures, management systems and internal controls at the bank's London branch were "seriously defective".
Adoboli was sentenced to seven years in prison last week after he was convicted of two counts of fraud.
Loading article content
Tracey McDermott, FSA director of enforcement and financial crime, said: "UBS's systems and controls were seriously defective.
"As a result, Adoboli was allowed to take vast and risky market positions, and UBS failed to manage the risks around that properly."