Alphabet (NASDAQ:GOOGL) vaulted to a $4 trillion market valuation on Monday, completing a dramatic narrative shift from a company once accused of losing its step in the artificial intelligence race to the world's second-most valuable public firm.
The Google parent’s stock has surged roughly 65% in 2025, outperforming its "Magnificent Seven" peers and recently overtaking Apple in market capitalization for the first time in nearly seven years.
The rally gained fresh momentum in early January after a flurry of reports confirmed Alphabet’s expanding dominance across the AI hardware and software stacks.
The primary catalyst for this $4 trillion milestone is the market's re-evaluation of Google Cloud.
Long considered a laggard behind Amazon and Microsoft, the unit has transformed into a high-margin growth engine.
In the third quarter of 2025, Cloud revenue jumped 34%, fueled by a record $155 billion backlog of sales contracts.
Investor sentiment was further bolstered by a rare technology bet from Warren Buffett’s Berkshire Hathaway, which disclosed a $4.3 billion stake in late 2025.
The "Oracle of Omaha" reportedly cited Google’s "zero-marginal-cost" advertising model and its superior vertical integration in AI as key reasons for the investment.