Billionaire Divergence: Warren Buffett's Amazon Exit vs. Ackman's Bold Entry

The investment world witnessed a striking contrarian moment in early 2025 when two legendary billionaire investors took opposite sides of the Amazon equation. Warren Buffett’s Berkshire Hathaway dramatically trimmed its Amazon holdings just as Bill Ackman’s Pershing Square Capital Management was aggressively accumulating shares. This divergence reveals fundamental disagreements about the e-commerce giant’s future value and strategic direction.

Buffett and Berkshire’s Strategic Retreat from Amazon

The fourth quarter of 2025 marked a significant turning point for Warren Buffett’s approach to Amazon. Berkshire Hathaway liquidated approximately 77% of its Amazon position—a stake the company had maintained since 2018. Despite seven years of ownership, Amazon never constituted a core holding in Berkshire’s portfolio, occupying less than 1% of its massive equity allocation.

Amazon faced substantial headwinds throughout 2025. President Trump’s tariff policies created margin compression across the company’s retail operations, particularly impacting products sourced from China and third-party sellers based internationally. These pressures cascaded through the business model, resulting in higher customer prices and reduced profitability on existing product lines.

The company’s recent earnings guidance further raised concerns among long-term value investors. Amazon projected capital expenditures of $200 billion in 2026—a significant jump from 2025 levels—predominantly directed toward AI infrastructure development. This massive capex commitment sparked investor skepticism about potential returns on such ambitious spending. For Warren Buffett’s typically conservative investment philosophy, the question became whether Amazon could generate acceptable returns from this intensity of capital deployment, particularly given the uncertain timeline for AI monetization.

Amazon’s valuation metrics have compressed considerably, now trading at approximately 26.5 times forward earnings. However, Buffett’s value investing framework emphasizes long-term competitive positioning. Concerns about Amazon’s competitive moat—specifically whether its artificial intelligence strategy could keep pace with rival tech firms—likely influenced the decision to substantially reduce exposure.

Ackman’s Contrary Conviction: Doubling Down on Amazon

While Buffett retreated, Bill Ackman moved decisively in the opposite direction. Pershing Square allocated 14% of its fund’s capital to Amazon, establishing it as the third-largest position in the portfolio. The timing was notably bold: Ackman’s team accumulated shares during April 2025, precisely when tariff-related chaos was at its peak. Since mid-April, the stock appreciated approximately 14%, validating the contrarian entry point.

Ackman’s investment thesis rests on Amazon’s ownership of “two category-defining franchises” with distinct competitive characteristics. The first is the core e-commerce platform, which generates $700 billion in annual gross merchandise value. This sprawling retail operation provides unmatched convenience—customers can order nearly any product and receive it within days through an unparalleled logistics network.

The second pillar is Amazon Web Services (AWS), which has evolved into a critical infrastructure provider for modern business. AWS allows companies to store data, run applications, and scale operations by renting capacity in Amazon-owned data centers. Critically, Pershing Square identified that AWS is currently operating at capacity constraints. This constraint transforms Amazon’s planned capex not as wasteful spending but as essential infrastructure expansion. Management guidance suggests data center capacity will double by 2027, positioning AWS for substantial revenue growth without execution risk.

Pershing’s analysis also identifies significant profitability potential within the e-commerce segment itself. Through higher-margin advertising revenue, improved network density, and warehouse automation powered by robotics, Amazon could nearly double profitability in retail operations. The integration of advanced robotics into fulfillment centers represents a genuine operational transformation that will reduce per-unit processing costs and accelerate delivery speed.

The Fundamental Question: AI Infrastructure or Profitability Burden?

The disagreement between Warren Buffett and Bill Ackman ultimately reflects two competing interpretations of Amazon’s capital strategy. Buffett views the $200 billion capex commitment with skepticism—concerned that the company may be overcommitting resources to an uncertain AI future without proven business applications. His conservative framework demands clarity on returns before endorsing massive capital deployment.

Ackman perceives the same capex through a different lens. Rather than viewing it as speculative spending, he sees it as necessary infrastructure investment that will drive competitive advantages in AWS and enable automation savings in e-commerce. The capacity constraints within AWS suggest that current infrastructure cannot support existing demand, making expansion economically justified rather than speculative.

Amazon’s core businesses have demonstrated remarkable resilience and dominance without artificial intelligence at the center of operations. The e-commerce platform serves hundreds of millions of customers globally, while AWS maintains market leadership in cloud infrastructure. Whether the company can successfully integrate AI capabilities to accelerate profitability remains an open question, but the underlying business assets retain substantial value regardless of AI outcomes.

Warren Buffett’s decision to reduce exposure reflects his traditional investment discipline—requiring demonstrable business quality and reasonable valuation before deploying capital. Bill Ackman’s contrarian accumulation reflects confidence in the company’s ability to navigate current challenges while developing next-generation competitive advantages. The outcome will ultimately depend on whether Amazon’s massive capex investment generates proportional returns, transforming the e-commerce and cloud industries in the process.