Shares of Credit Suisse plunged 60.5% in early trading Monday after the announcement that banking giant UBS would buy its troubled rival for almost $3.25 billion in a deal orchestrated by regulators to stave off further market-shaking turmoil in the global banking system.

UBS shares also were down 8% on the Swiss stock exchange.

Swiss authorities urged UBS to take over its smaller rival after a plan for Credit Suisse to borrow up to 50 billion francs ($54 billion) failed to reassure investors and the bank’s customers. Shares of Credit Suisse and other banks plunged last week after the failure of two banks in the U.S. raised questions about other potentially weak global financial institutions.

Markets remained jittery Monday despite the best efforts of regulators to restore calm. In the U.S., the Federal Deposit Insurance Corp. announced late Sunday that New York Community Bank has agreed to buy a significant chunk of the failed Signature Bank in a $2.7 billion deal.

Global stock markets sank, with Hong Kong’s main index sliding more than 3%. Market benchmarks in Frankfurt and Paris opened down more than 1%, with European banking stocks dropping more than 2%. Shanghai, Tokyo and Sydney also declined. Wall Street futures were off 1%.