The US tech giants Apple, Google’s parent Alphabet, Microsoft, Amazon and Facebook are the five biggest companies in the world by market capitalization. Their increasing dominance is fueling concerns about competition and data privacy.

So are regulators about to get tough?

Shares in Amazon and Alphabet raced past the $1,000-mark this month, the latest sign of the companies’ growing might.

Google is expected to attract more than 40% of digital advertising dollars this year; Amazon is on track to collect half of US online sales by 2021, according to at least one analyst