Alphabet Inc., Google’s parent company, crossed a historic $3 trillion market capitalization on Monday, September 15, 2025, driven by investor confidence in its artificial intelligence advancements and a favorable antitrust ruling, joining an elite group alongside Apple, Microsoft, and Nvidia.

Alphabet’s shares surged over 4% to close at $251.61 for Class A and $252.30 for Class C, both record highs, pushing its market cap to $3.05 trillion, according to data from the finance card above and reports from CNBC. The rally outpaced the Nasdaq’s 15% year-to-date gain, with Alphabet’s stock climbing more than 30% in 2025, making it the top performer among the "Magnificent 7" tech giants, surpassing the S&P 500’s 12.5% rise.

A key catalyst was a U.S. federal court decision in early September, where Judge Amit Mehta rejected the Department of Justice’s push to force Alphabet to divest its Chrome browser or Android operating system, despite finding Google guilty of maintaining an illegal search monopoly. The ruling, seen as lighter than anticipated, mandated data sharing with competitors but preserved Alphabet’s core structure, boosting shares by 9% post-verdict and adding over $230 billion to its valuation, per Reuters and Bloomberg. President Donald Trump publicly congratulated Alphabet, calling the outcome a "very good day" for shareholders.

Alphabet’s AI initiatives, particularly the Gemini model, have bolstered investor sentiment. The company reported a 32% revenue jump in its cloud-computing unit to $13.6 billion in Q2, driven by demand for AI-driven services, as noted in earnings calls. Google Search revenue grew 12% to $54.2 billion, fueled by AI features like Overviews, reaching over 2 billion users, and the Gemini app, with 450 million monthly active users. These advancements counter competition from OpenAI and Perplexity, which analysts say helped demonstrate market competition, softening regulatory penalties.

Despite its advertising business, which accounts for 78% of revenue, facing economic uncertainties, Alphabet’s diversified portfolio—including YouTube’s 13% ad revenue growth to $9.8 billion and ventures like Waymo—has reassured investors. The company trades at a forward price-to-earnings ratio of 23, lower than peers like Microsoft (33.9) and Apple (30.2), suggesting room for growth, per LSEG data. Analysts project a 13% revenue CAGR over three years, with cloud and AI as key drivers.