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.