Arbuthnot, which also runs wealth management and financial planning services, said its investment banking arm had nonetheless managed to remained profitable for the past year.
"Investment banking market conditions deteriorated sharply in the third quarter, leading to difficult trading for Arbuthnot Securities. Commission income was also impacted by the general decline in market volumes," the bank said in a statement.
The cost of carrying significant surplus deposits and of restructuring management had also impacted results for the quarter, the bank said.
However, it added that it had an encouraging corporate finance pipeline for the fourth quarter and that its private banking arm was trading strongly.