Exactly one year ago: Apple (AAPL) was the world's largest company with a market cap of $886 billion, Alphabet (GOOG) was the world's second largest company with a market cap of $769 billion, Microsoft (MSFT) was the world's third largest company with a market cap of $680 billion, and Amazon (AMZN) was the world's fourth largest company with a market cap of $603 billion.
Today, their market cap ranking has reversed: Amazon (AMZN) is the world's largest company with a market cap of $810 billion, Microsoft (MSFT) is the world's second largest company with a market cap of $789 billion, Alphabet (GOOG) is the world's third largest company with a market cap of $749 billion, and Apple (AAPL) is the world's fourth largest company with a market cap of $715 billion.
Over the past year: Amazon (AMZN)'s market cap has increased by 34.33%, Microsoft (MSFT)'s market cap has increased by 16.03%, Alphabet (GOOG)'s market cap has declined by 2.6%, and Apple (AAPL)'s market cap has declined by 19.3%.
Their combined market cap peaked on September 4th, 2018 at $3.792 trillion. On that day, Apple (AAPL)'s market cap reached $1.103 trillion and Amazon (AMZN)'s market cap reached $1 trillion. Afterwards, their combined market cap declined by $1.037 trillion or 27.35% to a low on December 24th, 2018 of $2.755 trillion, before bouncing by $308 billion or 11.18% to $3.063 trillion.