Amazon.com, Inc. (AMZN): Bill Ackman Is Loading Up on This Stock

Hedge fund Pershing Square (Bill Ackman) has materially increased its Amazon (AMZN.OQ) stake, first appearing with 5.8M shares in Q2 2025 and growing the position by 65% in Q4 2025 to 9.6M shares — about 15% of the fund’s 13F portfolio. The article frames this institutional buying alongside Amazon’s strategic pivot into AI infrastructure (large AWS investments), a commitment to invest up to an additional $25 billion in Anthropic (over $33 billion total), and growing high-margin ad and AI product monetization (Rufus: 300M users; ad-supported Prime Video: 315M viewers). Market impact: continued Pershing Square accumulation and Amazon’s AI/ad revenue initiatives are presented as bullish signals that could underpin AMZN shares and support structurally higher margins for AWS, making the stock attractive to long-term investors.