Credit Suisse has said it will borrow up to 50bn Swiss francs (£44.5bn) from the country’s central bank to shore up its finances.
The troubled banking giant said it is taking “decisive action” to strengthen and simplify its business.
Shares in Credit Suisse fell 24% on Wednesday after it said it had found “weakness” in its financial reporting.
Fears of a wider banking crisis sparked steep falls on stock markets, with Asian shares dropping.
However, markets in Europe are expected to open higher on Thursday.
Swiss National Bank, the country’s central bank, insisted Credit Suisse had the money it needed, but stressed it was ready to step in and help further if required.
Problems in the banking sector surfaced in the US last week with the shock collapse of Silicon Valley Bank, the country’s 16th-largest lender, followed two days later by the failure of New York’s Signature Bank.