Credit Suisse shares plunged on Monday after Swiss authorities cut a deal with its bigger rival UBS to acquire the troubled bank at a marked-down price.

But European bank stocks and the wider market gained as investors watch whether moves to shore up banks will stem further upheaval in the global financial system.

Shares of Credit Suisse, whose woes stem from questions over its internal controls, closed nearly 56 per cent lower a day after UBS said it would buy its fellow Swiss bank for a lowball price of 3 billion Swiss francs (US$3.25 billion). The shares traded at about the level they are valued at in the deal.