APPLE, MICROSOFT and (briefly) Amazon have all pulled it off. On January 16th Alphabet, Google’s parent company, became the fourth American company ever to have a market capitalisation of $1trn. Big Tech shares have continued to soar after a banner 2019, during which the quartet gained 46% in value, outpacing even America’s frothy stockmarket. Apple’s capitalisation has more than doubled since the start of last year, to $1.32trn. Add Facebook, and America Inc’s five most valuable firms have gained a cumulative $1.8trn in that period. Surely this cannot go on?

Maybe it can. The tech giants have continued to mint money despite President Donald Trump’s tech-infused trade war with China (a big manufacturer for Apple and Microsoft, as well as a large market). And they have so far survived controversies at home over abuses of user privacy (Facebook) or market power (mostly Alphabet, Amazon and Facebook).

Their full-year earnings reports, kicking off with Microsoft’s on January 23rd, will show as much. In the third quarter of 2019 the five firms’ cumulative net income totalled $40bn. A gusher of online-advertising dollars that fuels Google and Facebook shows no sign of petering out. Nor do the billowing cloud-computing businesses of Microsoft and Amazon. Apple has managed to offset falling iPhone sales with higher revenues from services (including a fresh video-streaming service) and must-have accessories such as its wireless earphones (it sold 67m pairs of AirPods in 2019).