It has been more than a year since three mid-tier banks collapsed in the US. Yet supervisors and central banks around the world are still trying to work out what to do to ensure the safety of these smaller banks without disrupting financial markets – especially the supply of credit.

The three banks in question – Silicon Valley Bank (SVB), Signature Bank and First Republic Bank – all buckled last year as solvency positions weakened due to the rising cost of funding, spooking depositors, prompting