Alphabet Inc. (GOOG) stock is up sharply in pre-market trading on November 17, 2025, with the current price at $289.91 (+4.67%). The rally follows Berkshire Hathaway's disclosure of a $4.3 billion stake in Alphabet, which sent shares up 6.1% to $293.40 in after-hours trading according to multiple reports. This major investment by Warren Buffett's firm has boosted investor confidence and triggered a strong upward move, outpacing broader market gains. The news is widely cited as the primary reason for Alphabet's price surge, with no other company-specific developments reported. Alphabet's performance today is directly tied to this high-profile investment, marking a significant vote of confidence from one of the world's most respected investors.