Whenever $17.5 billion global advertising giant Interpublic talks to its major clients – the likes of American Express, Coca-Cola, Johnson & Johnson and Spotify – about advertising on search engines, it presents them the same chart.

It reveals Google has 88.43 per cent market share in the US. Bing, owned by Microsoft, is second, with 6.21 per cent. Interpublic’s internal briefing document, titled “Market share for search engines in the U.S.A. … it isn’t even close”, surfaced in a Washington court in early October as part of the biggest competition lawsuit in two decades: the US Department of Justice’s case against tech titan Google.