Alphabet stock joined the club of companies with a market capitalization of more than $4 trillion.

The search giant crossed the $4 trillion line on Monday, rising to a peak of $4.009 trillion. It was the stock’s first time above that threshold, according to Dow Jones Market Data.

Alphabet has now joined Nvidia, Apple, and Microsoft as the only companies to ever cross the $4 trillion milestone.

Alphabet stock rose 1% on Monday to $331.86. News that the parent of Google has formed an artificial- intelligence partnership with Apple appeared to be behind the gain. Apple and Google said in a joint statement that the next generation of Apple Foundation Models will be based on Google’s Gemini models and cloud technology.

Those models will help power future Apple Intelligence features, including a more personalized Siri. The launch of the new Siri has been delayed until later this year.

Shareholders have been on a wild ride over the past 12 months. The stock hit a 52-week closing low of $144.70 on April 8, partly because the entire stock market took a hit following President Donald Trump’s “Liberation Day” tariff announcement on April 2. But concern about the remedies a judge could impose in an antitrust trial, plus worry that competing AI chatbots were winning market share in search, weighed on Alphabet shares specifically.

Now, the stock has bounced back, ending 2025 with a gain of 66%. A less severe antitrust decision than expected, research showing strong performance by Alphabet’s AI models, and positive data regarding Google’s search business, have reassured investors.