Billionaire Bill Ackman Just Sold This Hot Artificial Intelligence Stock. Here's Why Wall Street Thinks He Made a Big Mistake.

In Q3 2025 Bill Ackman refrained from new positions and largely de-risked rather than expanded Pershing Square’s concentrated 11-stock portfolio, trimming stakes in four names and notably selling just over 519,000 Alphabet Class A shares (about a 9.7% reduction), while leaving positions in Amazon and Alphabet Class C largely unchanged; Pershing Square still holds more than 11 million Alphabet shares worth roughly $3.3 billion. Wall Street remains overwhelmingly bullish on Alphabet—an S&P Global survey of 66 analysts showed zero sell ratings (12 strong buy, 45 buy)—supported by robust Q3 results (revenue $102.3bn, +16% y/y; earnings ~$35bn, +33%), accelerating Google Cloud growth, Gemini’s ~650m monthly active users, Waymo expansion plans and progress at Google Quantum AI. The most likely interpretation is profit-taking rather than a loss of conviction, and the article argues these AI and cloud catalysts underpin a continued long-term buy case for Alphabet.

Analysis

Bill Ackman refrained from initiating new positions in Q3 2025 and trimmed stakes in four holdings, notably selling just over 519,000 Alphabet Class A shares — a roughly 9.7% reduction — while leaving Amazon and Alphabet Class C largely unchanged and cutting Uber by only 0.1%. Pershing Square still holds in excess of 11 million Class A and Class B Alphabet shares with an estimated value near $3.3 billion, indicating the sale was a reallocation or profit-taking rather than a full exit.

Wall Street remains broadly bullish on Alphabet: an S&P Global survey of 66 analysts showed zero sell recommendations, with 12 strong buy and 45 buy ratings, supported by Alphabet’s Q3 results of $102.3 billion revenue (+16% y/y) and roughly $35 billion in earnings (+33% y/y). The company’s AI initiatives are material drivers — Gemini has over 650 million monthly active users, Google Cloud growth is accelerating, and the recent launch of Gemini 3.0 plus adoption of agentic AI are cited as near-term catalysts.

The most probable interpretation of Ackman’s move is disciplined profit-taking in a concentrated portfolio rather than a change in conviction, but the trim introduces short-term execution risk if other large holders follow suit. Key upside drivers cited are Google Cloud adoption, Gemini and agentic AI monetization, Waymo city expansions, and Google Quantum AI milestones; monitoring these metrics will be essential to validate the buy case and gauge whether further trimming occurs.

Key Decisions for Investors

• Consider initiating or incrementally adding long-term exposure to Alphabet to capture AI and cloud upside, but scale in positions to avoid buying into short-term profit-taking
• Monitor Google Cloud revenue trends, Gemini MAUs and agentic-AI adoption metrics, Waymo expansion milestones, and major-holder activity for signs the fundamental story is accelerating or that additional trims may signal distribution
• Manage position sizing given concentration risk — use phased purchases or partial allocations rather than full-sized buys to limit downside if Pershing Square or other large holders reduce exposure further