UBS, Switzerland's biggest bank, today posted a bigger than expected year-on-year rise in third-quarter net profit in part thanks to a tax benefit, while announcing a raft of changes to top management. 

The Zurich-based bank also detailed new performance targets for the coming years. 

This included pushing back a targeted adjusted return on tangible equity of above 15% to 2018 from 2016 previously. 

Net profit for the three months ended September was 2.1 billion Swiss francs ($2.1 billion), up from 762 million francs a year earlier and ahead of a forecast for 1.76 billion francs in a Reuters poll of four analysts. 

Earnings for the same period last year were hit by the bank setting aside 1.8 billion francs in legal reserves. 

The results were helped this quarter by a net tax benefit of 1.3 billion francs, largely from an increased valuation of UBS's deferred tax assets which it had flagged in the second quarter and is used to reduce the amount of tax due.

UBS chief executive Sergio Ermotti said he was pleased with the quarter as the bank navigated through jitters in emerging markets, triggered by fears over the strength of China's economy. 

"We stayed close to our clients in a very challenging environment," Ermotti said in a statement. 

On top of the results, UBS said its finance chief would shift roles among a raft of changes to its top management. 

From January, current chief financial officer Tom Naratil will take on the due role of president of UBS's wealth management business in the Americas and president of UBS Americas. 

Kirt Gardner, currently CFO for wealth management, will take over as group CFO.