Between them the seven – including Google's parent company Alphabet, online retailer Amazon, Facebook-owner Meta and electric car giant Tesla – account for a third of the benchmark S&P 500 index of top US companies.
But with a current stock market valuation of $3.6 trillion the iPhone maker is closely followed by microchip pioneer Nvidia, whose shares have had an amazing run, powered by the boom in artificial intelligence (AI) spending.
All this matters because even if you don't own these stocks directly, UK savers increasingly are exposed to their fortunes – especially if they are invested in tracker funds, which track indices such as the S&P 500, or technology-focused investment trusts.
To put these huge numbers into context, Apple is now as big as the entire annual output of the British economy, with Nvidia and Microsoft close behind – see table below.
But the big three have pulled away from the rest of the field – so much so that Alphabet, their nearest rival – is lagging on a valuation of 'just' $2.4 trillion.
