Credit Suisse Group yesterday played down rumours that it was seeking a major merger to keep up with Swiss rivals which plan to form the world's second biggest bank, United Bank of Switzerland.

But CS Group shares bucked a weak stock market. They jumped 5 per cent to 238 Swiss francs as merger speculation continued unabated following Monday's news that Union Bank of Switzerland (UBS) and Swiss Bank Corp (SBC) would merge. Swiss Reinsurance, which has cross share holdings with CS Group, advanced 8 per cent to 2,678 Swiss francs, bolstered by recurring rumours that the two planned some kind of alliance beyond their current product cooperation in risk management.