The Smart Money is Pulling Some Big Moves...

Key Concepts

• 13F Filings: Quarterly reports required by the U.S. Securities and Exchange Commission (SEC) from institutional investment managers with over $100 million in assets under management, disclosing their equity holdings.
• AWS (Amazon Web Services): Amazon’s cloud computing subsidiary, a major driver of profitability.
• Moat: A company’s ability to maintain competitive advantages over its rivals, protecting its long-term profits.
• Network Effect: The phenomenon whereby increased numbers of users enhance the value of a good or service.
• Glyoblastoma: An aggressive type of brain tumor.
• PE Ratio (Price-to-Earnings Ratio): A valuation ratio of a company’s stock price to its earnings per share.
• MAG 7: Refers to the seven largest US technology companies: Apple, Microsoft, Alphabet (Google), Amazon, Nvidia, Tesla, and Meta.

Major Investor Activity in Q4 2025 – 13F Filings Analysis

The recent 13F filings, covering the period ending Q4 2025, reveal significant activity from prominent investors, particularly regarding Amazon, Berkshire Hathaway’s portfolio shifts under Warren Buffett’s final filing as CEO, and Bill Aman’s new position in Meta. The filings were released 45 days after the end of Q4 2025.

Amazon: Increased Interest from Top Investors

Several high-profile investors demonstrated increased confidence in Amazon during Q4 2025. Seth Klarman of Baupost Group initiated a substantial new position in Amazon, allocating approximately $500 million to acquire 2.1 million shares, representing 9.28% of the Baupost portfolio – making it the second-largest holding. Bill Aman of Pershing Square increased his fund’s Amazon stake by 65%, building upon a position established in Q2 of the previous year. This now constitutes 14.28% of the Pershing Square portfolio, ranking as the third-largest holding behind Brookfield and Uber.

The rationale behind these investments appears to be driven by the anticipated impact of the “New Money” strategy being available for pre-order on Amazon, potentially boosting total revenue by an estimated 25%. However, a deeper analysis highlights the importance of Amazon’s two core business segments: retail and Amazon Web Services (AWS).

Amazon’s Business Segments (2025 Revenue Breakdown):

• Retail (North America & International): $588.2 billion (combined)
• Amazon Web Services (AWS): $128.7 billion

Despite generating significantly less revenue than the retail side, AWS is the more profitable segment.

Profitability Comparison (2025):

• Retail (North America): $29.6 billion operating profit
• Retail (International): $4.7 billion operating profit
• Amazon Web Services (AWS): $45.6 billion operating profit

This means AWS contributes 57% of Amazon’s total $80 billion operating profit, despite representing only 18% of its revenue. AWS is heavily focused on AI infrastructure, with Amazon planning $200 billion in capital expenditures for 2026. Bill Aman noted that AWS’s capacity was constrained by demand in 2025, and expects the doubling of data center capacity through 2027 to be rapidly absorbed by AI workloads. Amazon has recently secured AWS deals with numerous organizations including OpenAI, Visa, the NBA, BlackRock, and the US Air Force, indicating strong demand.

Interestingly, Berkshire Hathaway reduced its Amazon position by 77% during the same quarter, potentially signaling a different perspective on the stock’s valuation.

Berkshire Hathaway: The End of an Era

The Q4 2025 13F filing marks Warren Buffett’s final filing as CEO of Berkshire Hathaway, with Greg Abel and Ted Weschler poised to take greater control of the equity portfolio, particularly following Todd Combs’ departure to JP Morgan.

Berkshire Hathaway Portfolio Adjustments:

• Apple: Reduced stake by another 4%, now representing a portfolio percentage similar to American Express.
• Bank of America: Reduced stake by 9%.
• Chevron: Increased stake by 6.6%.
• Chubb: Increased stake by 9.3%.
• New York Times: Initiated a $350 million position, likely under Ted Weschler’s direction.

Warren Buffett’s long-term performance remains exceptional, with an average annual return of 19.9% since 1965, compared to 10.4% for the S&P 500. A $1 investment in Berkshire Hathaway in 1965 would now be worth over $55,000, versus $391 in the S&P 500.

Bill Aman’s Bet on Meta

Bill Aman’s Pershing Square fund established a new $1.76 billion position in Meta, making it the fifth-largest holding in the portfolio (11.37%). This investment occurred after Meta’s stock experienced a 25% decline from its Q3 2025 highs.

Aman’s thesis rests on three pillars: the AI opportunity, Meta’s strong “moat” (competitive advantage), and valuation. Pershing Square believes Meta is a leader in digital advertising and a key beneficiary of AI integration, with potential to improve content recommendations and ad targeting. Meta plans capital expenditures between $115 and $135 billion in 2026, representing an 87% increase from 2025.

Pershing Square emphasizes Meta’s powerful network effect, driven by its dominant platforms (Facebook, Instagram, Messenger, WhatsApp), providing a solid foundation for AI-driven improvements. Despite a 600% increase since its 2022 lows, Meta’s PE ratio currently stands at 22, which Pershing Square considers attractive compared to other companies in the MAG 7. They believe the current share price undervalues Meta’s long-term potential.

Other News

• Michael Burry: Closed his fund, Scion Asset Management, but is now more active on Twitter and Substack, sharing his investment thoughts publicly.
• Guy Spier: Closed his fund, Aquamarine Fund, due to health reasons (Grade 4 Glioblastoma). The New Money community is organizing a collection of letters and messages of support for Guy Spier, with submissions to be sent to hello@newcontact.

Conclusion

The Q4 2025 13F filings reveal a period of strategic repositioning by major investors. Increased interest in Amazon, driven by AWS’s growth and AI potential, contrasts with Berkshire Hathaway’s continued reduction of its Amazon stake. Bill Aman’s significant investment in Meta reflects confidence in the company’s AI strategy, strong network effects, and attractive valuation. The filings also mark a transition in leadership at Berkshire Hathaway and highlight the personal challenges faced by respected investors Michael Burry and Guy Spier. These filings provide valuable insights into the thinking of leading investors and offer potential avenues for further research and analysis.