Alphabet shares are now up more than 30% this year, compared with the 15% gain for the Nasdaq.
The $3 trillion milestone comes roughly 20 years after Google's IPO and a little more than 10 years after the creation of Alphabet as a holding company, with Google its prime subsidiary.
CEO Sundar Pichai was named CEO of Alphabet in 2019, succeeding co-founder Larry Page. Pichai's latest challenge has been the surge of new competition due to the rise of artificial intelligence, which the company has had to manage through while also fending off an aggressive set of regulators in the U.S. and Europe.
The rise of Perplexity and OpenAI ended up helping Google land the recent favorable antitrust ruling. The company's hopes of becoming a major artificial intelligence player largely ride with Gemini, Google's flagship suite of AI models.