The trillion-dollar question: can the tech giants keep growing?

A startling stock-market landmark for Apple has been offset by big falls for Facebook and Twitter. Is this tumultuous period just a blip, or the first sign of trouble?

It has been a tumultuous couple of weeks for America's high-flying technology stocks, even by their own unique standards. Their shares have been soaring since the start of the year, despite being buffeted by trade war fears as President Trump talked of limiting Chinese investments in the US and restricting American technology imports to China.

But now there are signs that cracks may be starting to appear in some of the biggest firms in the sector. Facebook suffered the biggest ever one-day drop in a company's market value - losing more than 90bn - after its growth slowed in the wake of the Cambridge Analytica scandal.