As the effects of the coronavirus pandemic swept through the global economy, the average observer could have been forgiven for missing a critical piece of news: by May 2020, the combined market capitalization of the four largest US tech companies reached one fifth of the entire S&P 500. Four companies – Microsoft, Apple, Amazon and Facebook – now account for 20 per cent of the combined value of the 500 largest US corporations – an unparalleled level of market concentration. Forty years these corporate entitites were either just beyond being plucky start-ups, or did not even exist.