Apple and Microsoft used to be the technology industry’s fiercest rivals. So when they report quarterly earnings on the same day, as they do today, it is a good moment to compare their fates. In early 2000 Microsoft had a market capitalisation of $534 billion, against Apple’s paltry $19 billion. Now Apple is worth $747 billion, more than any other listed company and about twice Microsoft’s $378 billion. The reversal of fortunes reflects the shift in computing away from desks and companies’ data centres, where Microsoft reigned, to mobile devices and the cloud. Today’s results will show how the two are dealing with the shift. The iPhone still fuels Apple’s growth engine; strong sales may allow the firm to do even better than expected. Microsoft, at last trying to end its dependence on the Windows operating system, is betting big on the cloud. It is likely to be the company’s fastest-growing business.