Mack: Popular choice with investors

Mr Mack, 57 this year, was until March president and chief operating officer of US rival Morgan Stanley Dean Witter.

He resigned from that post after being passed over for promotion.

Mr Wheat had come under increasing pressure after investigations were launched into allegations in the United States that CSFB had improperly allocated shares in initial public offerings to favoured clients.

In return, the bank received unusually large commissions, which amounted to kickbacks, it has been alleged.

Flaming Ferraris

CSFB has denied any wrongdoing although it did fire three brokers from its technology group in June in connection with the investigations.

The bank has also been under pressure in India where it was in April suspended from trading after allegations it helped an investor manipulate the stock market.

In Japan the previous month, a senior CSFB employee was convicted of violating market regulations and obstructing a government investigation.

And in 1999, the bank gained unwelcome attention in the UK when Lord Archer's son James was one of three traders - known collectively as the Flaming Ferraris - sacked following an investigation into alleged manipulation of the Swedish stock market.

Credit Suisse said Mr Wheat was leaving to pursue other interests and his departure was not related to the US investigation.

'Extremely credible'

The appointment of Mr Mack was popular with investors.

"He's extremely credible, come from a very strong capital markets background and has already been at the top job in the industry. It's a perfect fit," said Gary Goldstein, president of Wall Street recruitment firm Whitney Group.

Credit Suisse Group shares jumped 5% in early trading in Zurich.

Credit Suisse also announced a corporate reorganisation in which asset management is to be combined with CSFB under Mr Mack's management from January 2002.

Private banking and financial advisory services will form a second business unit.