A theory: let banks set their own deposit rates, let savers take their money elsewhere – for example, to stock markets – and those markets will thrive. It’s a theory that seems to be borne out by the FT’s finding that US banks made a cool $1 trillion by stiffing savers while the Fed’s base rates were (relatively) high at 5.5 per cent. At the end of Q2 this year the average US bank was paying 2.2 per cent on deposit accounts. In the UK, by contrast, it’s been easy to find easy-access savings accounts paying 4 per cent or more with the base rate at 5, thanks partly to a 14-point action plan introduced last year by the Financial Conduct Authority to make sure banks passed on high rates to savers. Is it by chance that in the past year the S&P 500 has risen more than four times faster than the FTSE 100?