Apple became the world’s most valuable publicly traded company when it surpassed ExxonMobil in August 2011.
Apple’s rise reflected the extraordinary commercial success of the iPhone, introduced in 2007, together with the growth of the iPod, Mac, and App Store businesses. Market capitalization is calculated by multiplying a company’s share price by its total number of outstanding shares, so a company can move ahead of a rival as investors revise expectations about future profits.
ExxonMobil had dominated the top position during the commodities boom, when high oil prices supported energy-company valuations. Apple’s ascent marked a major shift toward technology companies in global stock-market rankings. The comparison concerns market capitalization, not annual revenue, total assets, or cash holdings.
Apple has repeatedly exchanged the top ranking with Microsoft, Saudi Aramco, and other large companies as share prices and market conditions changed.