Zurich - The embattled Swiss banking giant UBS announced Thursday it appointed a new chief executive officer to replace Marcel Rohner, who resigned, at the top of the company.

"This represents a further step to restore stakeholder confidence and to pave the way back to success," UBS said in a statement.

The bank's board of directors said it appointed Oswald J. Grubel to the position of CEO with immediate effect. Grubel for decades worked at Credit Suisse, the second largest Swiss bank behind UBS.

"I will do all I can to bring UBS back on a profitable, successful track," Gruble said.

UBS, the largest wealth manager, has been hit recently on two main fronts.

The bank made huge writedowns last year after being affected by the financial fallout in the US more than other European banks and eventually took a bailout from the Swiss government and central bank.

It has also been entangled in a legal battle in the United States over tax fraud allegations. UBS admitted its employees conducted improper actions and last week agreed to pay a fine of 780 million dollars to US authorities and hand over some client data.

UBS, under orders from the Swiss regulatory body FINMA, transferred data on some 250 to 300 clients, according to reports though there is no official confirmation on the figure.

The handover has sparked concerns about the future of Swiss banking secrecy laws.

While the US was demanding data on 52,000 more clients, UBS said it would put up a legal fight to this, which would likely end up in court in the summer.

Some in Switzerland have said UBS acted too hastily in handing over secrets. Other criticism focused on the US and UK, who were accused of double dealing as they allowed for tax havens and shell companies, but were unfairly coming down on Switzerland.

The handover was done based on the differentiation in Swiss law between tax evasion and tax fraud, where in the latter event the secrecy principles can be violated.

Without the banking secrecy there was concern for the viability of the Swiss financial sector, which makes up about 12 per cent of the Alpine nation's GDP.

Luxembourg's financial regulator also denounced UBS on Tuesday, saying there was a "serious failure" in its surveillance role over a fund in its custodianship which funneled over 1.4 billion dollars to the Bernard Madoff's alleged Ponzi scheme.

UBS said the accusation was not correct and that it did not have "responsibility" to Luxembourg shareholders "for the unfortunate results of the Madoff scandal." (dpa)