Berkshire Hathaway’s Alphabet stake has surged $415 million in just a week, reaching nearly $5.35 billion as shares climbed 8.4%. The move has reignited debate over whether the traditionally cautious firm is warming to high-risk, AI-driven growth. Alphabet’s rally was boosted by Berkshire’s disclosure and positive reception of Google’s new Gemini 3 AI model, even as other tech stocks lagged.