The chief executive of the world’s biggest money manager has warned that more banks could collapse, as Swiss regulators were last night forced to reassure investors that Credit Suisse was not at risk.

Larry Fink, the chief executive of Blackrock, said the recent failure of Silicon Valley Bank, Silvergate and Signature Bank in the US could be the start of a “slow, rolling” crisis that may see others fail.

The warning, made in his annual letter to investors, came as shares in Credit Suisse plunged by as much as 30pc on Wednesday, triggering a wave of panic and speculation that it may be forced into a bailout.

Late last night the Swiss National Bank and regulator FINMA issued a joint statement reassuring investors that Credit Suisse remained financially sound.

Officials said “the problems of certain banks in the USA do not pose a direct risk of contagion for the Swiss financial markets” but pledged to provide emergency liquidity support for Credit Suisse if needed.

The US Treasury said it was monitoring the situation and was in touch with other officials around the world about the crisis.

Credit Suisse has insisted its finances are sound but investors are growing increasingly nervous about the banking sector after the recent run of US failures.

Barclays fell 9pc and HSBC dropped 4pc in London, where the FTSE 100 closed down 3.8pc. The drop wiped £75bn off the value of the index, which was the ninth biggest daily drop by value in its history.

Mr Fink, who oversees $10trn of assets at BlackRock, said recent bank failures in the US were the “price of easy money” and warned there could be more “domino[es] to fall”.

He wrote: “This past week we saw the biggest bank failure in more than 15 years as federal regulators seized Silicon Valley Bank. This is a classic asset-liability mismatch. Two smaller banks failed in the past week as well. It’s too early to know how widespread the damage is.

“The regulatory response has so far been swift, and decisive actions have helped stave off contagion risks. But markets remain on edge.”

Mr Fink, who is one of the world's most influential investors, said banks were running into difficulties because of higher interest rates, which were putting pressure on the business models of some lenders. Interest rates have risen rapidly in the US over the last year, climbing from near zero to approaching 5pc.

Mr Fink said: “Prior tightening cycles have often led to spectacular financial flameouts – whether it was the Savings and Loan Crisis that unfolded throughout the eighties and early nineties or the bankruptcy of Orange County, California, in 1994.

“In the case of the S&L Crisis, it was a ‘slow rolling crisis’ – one that just kept going. It ultimately lasted about a decade and more than a thousand thrifts went under.”

The collapse of smaller American savings and loan institutions in the 1980s and 1990s ultimately cost the economy $160bn.

Mr Fink said: “We don’t know yet whether the consequences of easy money and regulatory changes will cascade throughout the US regional banking sector (akin to the S&L Crisis) with more seizures and shutdowns coming.”

Mr Fink said it seemed “inevitable” that some banks would now need to pull back on lending and shore up their balance sheets, likely prompting many to turn to capital markets for support.

At the same time, he said regulators were likely to tighten capital standards.

His comments came as trouble at Credit Suisse sent shockwaves through European stock markets.

Shares in the Swiss bank crashed after the lender’s biggest investor, the Saudi National Bank, ruled out providing it with fresh funding.

Credit Suisse has lurched from crisis to crisis and the worsening economic backdrop has triggered fears it may be forced into a bailout.

Concerns about a possible global banking crisis rippled out across the market. Oil prices plunged to their lowest level since December 2021, with the price of Brent crude tumbling 4.7pc to just under $74 a barrel.

Robert Yawger, director of energy futures at Mizuho in New York, told Reuters that traders were “pulling the plug across different instruments”.

He said: “Nobody wants to go home with a big position on anything today. You have nowhere to hide really.”

Mr Fink also warned in his letter on Wednesday that the world is sleepwalking into a “silent” retirement crisis as people live longer.

He said: “It doesn’t make headlines or attract attention because it’s not immediate. It’s not this year’s – or even next year’s – problem. But it is a crisis. And the longer we delay the conversation about it, the larger the crisis grows.”

Ageing populations and lower birth rates will make affording retirement “more challenging than ever”, he said. Elderly people will be forced to spend more on healthcare and housing as shrinking tax bases make generous state pensions less affordable, he warned.

At the same time, many people – even in wealthy countries – “lack the ability to save”. Those who can are not putting enough assets into investment that will yield sufficient money for a comfortable retirement.

He said: “In some countries people are actually over saving but under-investing. If they are keeping their money in the bank rather than investing in the market, they won’t generate the returns necessary to retire with dignity.”

Mr Fink blamed “fear” about economic uncertainty, financial institutions and crises such as the pandemic and the Ukraine war.