A dive in revenues at Bank of America Merrill Lynch's sales and trading division helped push its global banking and markets division into a post-tax loss despite booking a substantial gain from a fall in the value of its own debt, in results which one analyst described as “brutal”.

Total revenue in the US bank's investment bank hit $5.2bn in the third quarter, which was down 23% on the previous three months, with pre-tax profit falling to $727m, down two-thirds in that period.