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.
The BBC understands that the Bank of England has been in touch with Credit Suisse and the Swiss authorities to monitor the situation.
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.
The US central bank had been forced to step in to prevent a run on bank deposits as panic spread.
Sir John Gieve, former deputy governor at the Bank of England, told the BBC that central banks were sending a "message" that such problems would be contained locally.
He added that in Credit Suisse's case, this was likely to be enough to stop the crisis spreading.
"What we've seen overnight is the Swiss central bank saying no, we will not let this get into a disorderly collapse," he told the BBC's Today programme.
"I don't know what the future for Credit Suisse holds but so far they are still standing and it looks like the Swiss central bank will ensure it's standing long enough to rearrange its affairs for the future."
Japan's Nikkei 225 index was down by 1.1% in late midday trading, with markets in Hong Kong and Sydney down by over 1.5%. The Shanghai Composite lost 0.5%.
'Material weaknesses'
Credit Suisse, founded in 1856, has faced a string of scandals in recent years, including money laundering charges, spying allegations and high profile departures.
It lost money in 2021 and again in 2022 and has warned it does not expect to be profitable until next year.
The bank's disclosure on Tuesday of "material weakness" in its financial reporting renewed investor concerns.
Daniel Davies, managing director at Frontline Analysts, and a former bank analyst at Credit Suisse, said that the bank's "millionaire and billionaire client base just seems to have reached the end of their tolerance and they've been taking money out over the last six months at what began to look like an increasing rate".
He added that the Bank of England will have been asking its Swiss counterpart whether it still had faith in Credit Suisse.
"Because the nature of these crises is that when you have a real massive deposit run it is like a tsunami - nothing humans can make can stop it. The only thing you can do is stop it before it turns into a proper deposit run and the only people that can do that are the central banks."
These were intensified when the Saudi National Bank, Credit Suisse's largest shareholder, said it would not buy more shares in the Swiss bank on regulatory grounds.
On Wednesday shares in the lender plunged as other banks rushed to pull out their funds from the bank and prime ministers in Spain and France spoke out in an attempt to ease fears.
The collapse of Silicon Valley Bank has also fuelled concerns about the value of bonds held by banks, as rising interest rates made those bonds less valuable.
Central banks around the world - including the US Federal Reserve and the Bank of England - have sharply increased interest rates as they try to curb the rate of price rises, or inflation.
Banks tend to hold large portfolios of bonds and as a result are sitting on significant potential losses.
The falls in the value of bonds held by banks is not necessarily a problem unless they are forced to sell them.
Silicon Valley Bank - which specialised in lending to technology companies - was shut down on Friday by US regulators in what was the largest failure of a US bank since 2008.