Apple made Wall Street history on Wednesday when its market value pushed past $2 trillion (€1.68 trillion), the first time a US company has broken the record.
Apple shares have more than doubled from a March low, in a rally that has been driven by strong earnings results and optimism over its upcoming 5G iPhone and as it defied the global slump in consumer spending stemming from the Covid pandemic.
Apple's position as the most valuable company in the world is good news for staff including more than 6,000 in Ireland who in many cases have had the option to have some of their income paid in shares over the past three decades.
The sight of Apple's already high valuation doubling in a year may well attract further regulatory and competition authority scrutiny to the company which has face huge push back from political leaders for its ability to minimise its tax liabilities on global income, including historically the use of Irish companies. But, policymakers' appetite to take on Apple may be tempered after the company and Ireland won an appeal this summer against a case brought by then-EU Competition Commissioner Margrethe Vestager in which she had sought to claw back €13bn in taxes which the Commission deemed State aid.
Amazon.com and Microsoft are the second and third-largest US stocks, and have market caps under $1.7 trillion.
Oil giant Saudi Aramco briefly boasted a $2 trillion valuation in December, but shares of Saudi Arabia's national oil company and fallen since and it currently a market cap of around $1.8 trillion.
US firms dominate a ranking of the world's biggest corporations by market capitalisation, followed by China. Europe's most valuable companies are both Swiss - Nestle and Roche, according to statistics complied in June by accountancy firm PwC.
The PwC list placed just three European Union-based companies among the world's 50 most valuable stock market listed businesses, LVMH and L'Oreal of France and German software giant SAP.
Apple last month reported quarterly sales that far exceeded forecasts as consumers snapped up new iPhones, Mac computers and iPads as well as its services during the lockdowns.
Additional reporting: Bloomberg