Alphabet's market capitalization surpasses $4 trillion, partnering with Apple Siri to strengthen its AI dominance

Alphabet closed at $332.73 on Monday, reaching a new all-time high and officially announcing its entry into the “$4 Trillion Club,” becoming one of the few tech giants to surpass this market capitalization threshold after Nvidia, Apple, and Microsoft. This rally was mainly driven by market confidence in its artificial intelligence (AI) strategy, especially with recent reports of a multi-year key partnership agreement with Apple. This agreement will leverage Google’s AI technology to support the iPhone ecosystem, including enhancing Siri’s voice assistant capabilities, seen as a win-win strategic move. Alphabet continued the strong momentum from 2025, when its stock surged over 65% for the year, and has risen nearly 5% so far this year, indicating renewed investor confidence in its leadership in generative AI.

Rising to the second-largest global company by market cap, closely trailing Nvidia

With its market cap surpassing $4 trillion, Alphabet has overtaken Apple to become the second-largest company worldwide, behind only Nvidia, which has recently crossed the $5 trillion mark. Over the past year, Alphabet’s stock performance outpaced most of the other members of the FAANG group, with its market cap increasing by nearly $1.5 trillion in 2025 alone. This reflects the capital market’s higher valuation of companies capable of autonomous chip development (TPU) and large language models. Despite fierce market competition, Alphabet has successfully mitigated concerns about emerging rivals like OpenAI through its solid financial health and technological moat.

Deepening strategic alliance with Apple to empower Siri’s upgrade

The key positive driver behind Monday’s stock rally was the signing of a multi-year cooperation agreement between Alphabet and Apple. Google will become one of the key technology suppliers behind Apple’s “Apple Intelligence,” utilizing its advanced AI models to drive various iPhone features, with the most critical being the modernization of Siri. By integrating Google’s technology, Siri will gain stronger natural language understanding and generation capabilities. For Alphabet, this not only means licensing revenue from technology output but also locks in billions of Apple devices worldwide as traffic sources for its AI models, greatly enhancing its data moat.

Valuation rebounding to recent highs, Berkshire Hathaway’s stake provides a boost

As market sentiment turns more optimistic, Alphabet’s forward P/E ratio has reached 28, the highest since 2021, significantly above its 10-year average of 20.5; in mid-2025, its P/E ratio had dipped to around 14. Despite the sharp increase in valuation, Alphabet still trades at a slight discount compared to the overall US tech giants index. Additionally, value investing indicators have emerged, with Berkshire Hathaway revealing in November last year that it had built a position in Alphabet during Q3, further reinforcing institutional investor confidence in its long-term value.

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