Chaos theory proposes that a butterfly flapping its wings in one place can cause a tornado in another. Similarly, the recent failure of a niche California US tech lender this week pushed an unrelated Swiss bank close to collapse. Time for central bankers to acknowledge that with risks unpredictable, rate policy must be more cautious.

The crash of Silicon Valley Bank and a financial crisis at Credit Suisse were reactions to globally rising rates and connected via contagious panic.

This forced the Swiss lender to go cap in hand to the Swiss National Bank 350 metres down the street in Zurich. The SNB has put up SFr50bn ($54bn) in extra liquidity. Presumably, some big counterparties were shunning Credit Suisse despite a tolerable liquidity coverage ratio.