The investing world was shocked last week by block trades worth billions of dollars in highly visible shares —which, it emerged, was thanks to positions being swiftly closed by Wall Street in order to try and evade the fallout of the collapse of the Archegos Capital Management hedge fund. Archegos is the family office of Bill Hwang, who is forbidden by regulators in the US and Hong Kong from managing outside clients’ money. This was because he was accused of violating trading rules at his former hedge fund. Under most regulatory systems, family offices can be more lightly supervised, since they are essentially private wealth management vehicles of extremely wealthy individuals. Certainly, banks are not as undercapitalised now as they were in the run-up to the 2008 financial crisis. But the splash zone created by the sinking of Mr Hwang’s Archegos means regulators globally will have to ask some tough questions anyway.