GENEVA (AP) — Fears about the world banking system spread to Europe on Wednesday as shares in the globally connected Swiss bank Credit Suisse plunged and dragged down other major European lenders in the wake of bank failures in the United States.

At one point, Credit Suisse shares lost more than a quarter of their value, hitting a record low after the bank’s biggest shareholder — the Saudi National Bank — told news outlets that it would not put more money into the Swiss lender, which was beset by problems long before the U.S. banks collapsed.

The turmoil prompted an automatic pause in trading of Credit Suisse shares on the Swiss market and sent shares of other European banks tumbling, some by double digits. That fanned new fears about the health of financial institutions following the recent collapse of Silicon Valley Bank and Signature Bank in the U.S.

Speaking Wednesday at a financial conference in the Saudi capital of Riyadh, Credit Suisse Chairman Axel Lehmann defended the bank, saying, “We already took the medicine” to reduce risks.

When asked if he would rule out government assistance in the future, he said: “That’s not a topic. … We are regulated. We have strong capital ratios, very strong balance sheet. We are all hands on deck, so that’s not a topic whatsoever.”

But Switzerland’s central bank announced late Wednesday that it was prepared to act, saying it would support Credit Suisse if needed. A statement from the bank did not specify whether the support would come in the form of cash or loans or other assistance. At the moment, regulators said, they believe the bank has enough money to meet its obligations.

Credit Suisse then said early Thursday that it is taking measures to shore up its finances, including exercising an option to borrow up to 50 billion francs ($53.7 billion) from the central bank.

“This additional liquidity would support Credit Suisse’s core businesses and clients as Credit Suisse takes the necessary steps to create a simpler and more focused bank built around client needs,” the bank said.

A day earlier, Credit Suisse reported that managers had identified “material weaknesses” in the bank’s internal controls on financial reporting as of the end of last year. That fanned new doubts about the bank’s ability to weather the storm.

Credit Suisse stock dropped about 30%, to about 1.6 Swiss francs ($1.73), before clawing back to a 24% loss at 1.70 francs ($1.83) at the close of trading on the SIX stock exchange. At its lowest, the price was down more than 85% from February 2021.

After the joint announcement from the Swiss National Bank and the Swiss financial markets regulator, the shares also made up some ground on Wall Street.

The stock has suffered a long, sustained decline: In 2007, the bank’s shares traded at more than 80 francs ($86.71) each.

With concerns about the possibility of more hidden trouble in the banking system, investors were quick to sell bank stocks.

France’s Societe Generale SA dropped 12% at one point. France’s BNP Paribas fell more than 10%. Germany’s Deutsche Bank tumbled 8%, and Britain’s Barclays Bank was down nearly 8%. Trading in the two French banks was briefly suspended.

The STOXX Banks index of 21 leading European lenders sagged 8.4% following relative calm in the markets Tuesday.

The turbulence came a day ahead of a meeting by the European Central Bank. President Christine Lagarde said last week, before the U.S. failures, that the bank would “very likely” increase interest rates by a half percentage point to fight against inflation. Markets were watching closely to see if the bank carries through despite the latest turmoil.

Credit Suisse is “a much bigger concern for the global economy” than the midsize U.S. banks that collapsed, said Andrew Kenningham, chief Europe economist for Capital Economics.

It has multiple subsidiaries outside Switzerland and handles trading for hedge funds.

“Credit Suisse is not just a Swiss problem but a global one,” he said.

He noted, however, that the bank’s “problems were well known so do not come as a complete shock to either investors or policymakers.”

The troubles “once more raise the question about whether this is the beginning of a global crisis or just another ‘idiosyncratic’ case,” Kenningham said in a note. ”Credit Suisse was widely seen as the weakest link among Europe’s large banks, but it is not the only bank which has struggled with weak profitability in recent years.”

Leaving a Credit Suisse branch in Geneva, Fady Rachid said he and his wife are worried about the bank’s health. He planned to transfer some money to UBS.

“I find it hard to believe that Credit Suisse is going to be able to get rid of these problems and get through it,” said Rachid, a 56-year-old doctor.

The Swiss National Bank declined to comment. The Swiss Financial Market Supervisory Authority did not immediately respond to calls and emails seeking comment.

Investors responded to “a broader structural problem” in banking following a long period of low interest rates and “very, very loose monetary policy,” said Sascha Steffen, professor of finance at the Frankfurt School of Finance & Management.

In order to earn some yield, banks “needed to take more risks, and some banks did this more prudently than others.”

Now investors are worried that banks “have risks on their balance sheet that they don’t know about and therefore have accumulated significant losses that haven’t been yet realized.”

European finance ministers said this week that their banking system has no direct exposure to the U.S. bank failures.

Europe strengthened its banking safeguards after the global financial crisis that followed the collapse of U.S. investment bank Lehman Brothers in 2008 by transferring supervision of the biggest banks to the central bank, analysts said. The central bank is considered less likely than national supervisors to look the other way at developing problems.

The Credit Suisse parent bank is not part of EU supervision, but it has entities in several European countries that are. Credit Suisse is subject to international rules requiring it to maintain financial buffers against losses as one of 30 so-called globally systemically important banks, or G-SIBs.

Share prices plunged after Saudi National Bank Chairman Ammar Al Khudairy told Bloomberg and Reuters that the bank has ruled out further investments in Credit Suisse to avoid regulations that kick in with a stake above 10%.

The Saudi National Bank has invested some 1.5 billion Swiss francs to acquire a holding just under that threshold.

The Swiss bank has been pushing to raise money from investors and roll out a new strategy to overcome an array of troubles, including bad bets on hedge funds, repeated shake-ups of its top management and a spying scandal involving Zurich rival UBS.

In an annual report released Tuesday, Credit Suisse said customer deposits fell 41%, or by 159.6 billion francs ($172.1 billion), at the end of last year compared with a year earlier.

___

McHugh reported from Frankfurt, Germany. Associated Press writers Joseph Krauss in Ottawa, Ontario, and Angela Charlton in Paris also contributed.