UBS returned to a modest profit at its investment bank in the fourth quarter and struggled to attract new client money to its wealth management business, showing chief Oswald Gruebel still has a way to go to turn around the bank.

Gruebel's overhaul of the investment bank started to pay off in the fourth quarter as equities and fixed income, commodities and currencies revenues improved, though bigger losses on the bank's own credit again kept net profit to just 75 million Swiss francs ($78.35 million) after a surprise loss for the previous three months.

But UBS's core wealth management arm made little progress winning new money after clients rattled by massive writedowns on toxic assets and a damaging tax dispute with the United States have pulled out nearly 400 billion francs in recent years.

The bank booked net money outflows for the third year running, despite Q4 being the second consecutive quarter of modest client money growth.