Breaking down the stocks Guy Spier (Aquamarine) bought, sold, and held in Q4 2025, including their holdings at the end of the quarter. All data sourced from Aquamarine's 13F filed on January 15, 2026.
Who are Guy Spier and Aquamarine Capital?
Guy Spier is the founder and portfolio manager of Aquamarine Fund (commonly referred to as Aquamarine Capital). The fund is known for its highly concentrated portfolio, typically consisting of 10-15 stocks, with the top 7 holdings comprising approximately 75% of assets, and cash holdings averaging around 5-6% when attractive opportunities are limited. His investment strategy is a global value investing approach inspired by Warren Buffett's original 1950s partnerships, emphasizing long-term compounding of intrinsic value and capital preservation while avoiding leverage and excessive trading. Spier focuses on undervalued, high-quality companies that occupy the "economic high ground," with strong qualitative factors like economic moats, high returns on invested capital, share repurchase programs, resilient brands, ecosystem control, and the ability to endure and compound sustainably over decades, often in sectors like financial services, luxury goods, and emerging market infrastructure.
Guyspier.com
Aquamarinefund.com
Guy Spier on X
Q4 '25 13F filed with SEC
Holdings in Q4 2025
| Ticker | Company | Weight | Change | Value |
|---|---|---|---|---|
| BRK-B | Berkshire Hathaway | 33.3% | Trimmed (-31%) | $49.06M |
| AXP | American Express | 16.3% | Trimmed (-69%) | $24.05M |
| MA | Mastercard | 15.5% | Trimmed (-39%) | $22.84M |
| BRK-A | Berkshire Hathaway | 15.3% | $22.64M | |
| MCO | Moody's | 9.3% | $13.79M | |
| RACE | Ferrari | 6.5% | Trimmed (-50%) | $9.56M |
| DJCO | Daily Journal | 3.8% | $5.6M | |
| BAC | Bank of America | 0.0% | Exited | $-39.61M |
| MU | Micron | 0.0% | Exited | $-13.39M |
| BABA | Alibaba | 0.0% | Exited | $-8.49M |
| GOOGL | Alphabet | 0.0% | Exited | $-3.89M |
| SRG | Seritage Growth Properties | 0.0% | Exited | $-2.12M |
| AMR | Alpha Metallurgical | 0.0% | Exited | $-1.31M |
| CNR | Core Natural Resources | 0.0% | Exited | $-897K |
Current Investment Strategy
Guy Spier's Aquamarine Fund dramatically consolidated its portfolio in Q4 2025, exiting five positions including Bank of America, Micron, Alibaba, Alphabet, and Seritage Growth Properties to concentrate its $147.5 million in assets across just seven holdings anchored by Berkshire Hathaway, Moody's, and Daily Journal. The Buffett disciple's intensified focus reflects his unwavering commitment to owning businesses with durable competitive moats and superior capital allocation, with financial services and payments franchises comprising the overwhelming majority of the ultra-concentrated value portfolio.
New Investments
Aquamarine did not open any new positions during Q4 2025.
Added, Trimmed, and Exited
Added
Aquamarine made no additions to existing positions this quarter.
Trimmed
Guy Spier significantly reduced four core holdings: American Express (AXP) was cut by 145,000 shares (-69%), Ferrari (RACE) was halved with a 30,000-share reduction (-50%), Berkshire Hathaway (BRK-B) was trimmed by 43,000 shares (-31%), and Mastercard (MA) was reduced by 25,750 shares (-39%).
What it means: These substantial trims across some of Aquamarine's highest-conviction financial services and luxury holdings suggest profit-taking after strong performance in these quality compounders. The simultaneous reduction in multiple positions indicates Spier may be raising significant cash, possibly in anticipation of better opportunities ahead or reflecting caution about elevated valuations in premium businesses.
Exited
Aquamarine completely liquidated seven positions: Bank of America (BAC) ($39.6M), Micron (MU) ($13.4M), Alibaba (BABA) ($8.5M), Alphabet (GOOGL) ($3.9M), Seritage Growth Properties (SRG) ($2.1M), Alpha Metallurgical (AMR) ($1.3M), and Core Natural Resources (CNR) ($897K).
What it means: This sweeping exit from multiple sectors—banking, semiconductors, Chinese tech, real estate, and coal—represents a dramatic portfolio simplification. The departure from cyclical names like BAC, MU, and the metallurgical coal plays, combined with exiting BABA and GOOGL, suggests Spier is concentrating the portfolio into his highest-conviction holdings while reducing exposure to economically sensitive and geopolitically uncertain positions. This leaves Aquamarine with a highly focused portfolio centered on Buffett-affiliated companies and quality financial franchises.
Disclaimer: All posts are for informational purposes only. They are NOT a recommendation to buy or sell the securities discussed. Please do your own research and due diligence before investing your money.
