Alphabet, one of the world's largest companies by market cap, was created in 2015 as the parent company of Google.
Google's founders, Larry Page and Sergey Brin, announced the Alphabet restructuring in August 2015. Alphabet became the publicly traded parent, while Google remained its largest subsidiary and continued operating its search, advertising, Android, YouTube, and cloud businesses.
The restructuring separated Google's core internet products from several other ventures, including research and investment activities. Page became Alphabet's chief executive, and Sundar Pichai became Google's chief executive at the time of the change.
Alphabet's market capitalization is the combined value investors place on its publicly traded shares. It should not be confused with Google's original 1998 founding date: Alphabet is the later corporate structure created around Google.