Royal Bank of Scotland said Friday that annual net losses more than trebled to £6.95 billion ($8.7 billion, 8.2 billion euros) in 2016 on litigation and restructuring costs.
RBS, bailed-out by the British government following the 2008 financial crisis, posted its ninth consecutive annual loss last year.
Its loss after tax for 2016 ballooned from a net loss of £1.98 billion a year earlier, RBS said in a statement.
The Edinburgh-based lender said it had been hit by litigation and conduct costs of almost £5.9 billion, including over its issuance of US mortgage-backed securities and role in the mis-selling of a UK insurance product.
It suffered also restructuring charges totalling £2.1 billion during 2016.
"These costs are a stark reminder of what happens to a bank when things go wrong and you lose focus on the customer, as this bank did before the financial crisis," RBS chief executive Ross McEwan said in the statement.
RBS is around 73-percent owned by the British government after the lender was saved with £45.5 billion of taxpayers' cash in the world's biggest banking bailout at the height of the global financial crisis.
In recent years, McEwan has overseen a massive overhaul of operations, slashing the bank's investment banking activities and axeing thousands of jobs.
On Friday, RBS said it would slash operating expenses by a further £2 billion over four years, with £750 million of savings being made in 2017.