Ackman Boosts Amazon Stake 65% as Buffett Cuts 77%, Stock Up 10% YTD Near $264

Billionaire investors Warren Buffett and Bill Ackman diverged sharply on Amazon.com Inc in Q4, with Buffett trimming his stake by 77% to ~0.1% of Berkshire's portfolio while Ackman increased his by 65% to ~14% of Pershing Square's. This contrast highlights differing views on Amazon's AI-driven AWS growth amid recent recovery from late-2025 weakness. Shares have risen ~10% year-to-date, trading near $264 with a $2.8 trillion market cap, as institutional flows and strong earnings momentum drive upward pressure and reassess AI demand risks.