Britain's financial regulator said on Monday it had fined Swiss bank UBS £29.7 million (36.7 million euros, $47.6 million) for failings that allowed Kweku Adoboli to commit the country's biggest fraud.
Adoboli, 32, was jailed last week for seven years after gambling away $2.3
billion (1.8 billion euros) of the lender's money.
"UBS's systems and controls were seriously defective," said Tracey McDermott, director of enforcement and financial crime at Britain's Financial Services Authority (FSA) watchdog.
A jury in London last week found the Ghanaian-born banker guilty of two counts of fraud, though it cleared him of four charges of false accounting.