Think of an industry in which three big companies have used technology and economies of scale to become oligopolies and wield power over other enterprises. It hails not from Silicon Valley but the US east coast.

The industry in question is passive investment management, in which computers take the role of human stock pickers and money is channelled into index and exchange traded funds. The Big Three of the US industry — BlackRock, Vanguard and State Street — have gained such size and efficiency that they control 80 per cent of the money invested in US index funds.