On Thursday, stock markets around the world suffered their most severe declines since the height of market volatility in March, when the Covid-19 pandemic began to affect Europe and the Western world in earnest. The US S&P index fell by over 4 per cent, the UK’s FTSE fell by around 4 per cent and Germany’s DAX index fell by around 3 per cent. The declines were due to a number of factors: stretched valuations, concerns regarding a second Covic-19 wave and the US Federal Reserve’s economic outlook. First, valuations had become quite frothy in recent weeks. The US S&P benchmark…