Breaking down the stocks Guy Spier (Aquamarine) bought, sold, and held in Q2 2025, including their holdings at the end of the quarter. All data sourced from Aquamarine's 13F filed on July 16, 2025.
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
Q2 '25 13F filed with SEC
Holdings in Q2 2025
| Ticker | Company | Weight | Change | Value |
|---|---|---|---|---|
| BRK-B | Berkshire Hathaway | 22.0% | $68.3M | |
| AXP | American Express | 21.6% | $66.99M | |
| MA | Mastercard | 11.9% | $36.95M | |
| BAC | Bank of America | 11.7% | $36.33M | |
| RACE | Ferrari | 8.1% | $24.97M | |
| MU | Micron | 8.0% | $24.65M | |
| BRK-A | Berkshire Hathaway | 7.1% | $21.86M | |
| MCO | Moody's | 4.4% | $13.54M | |
| BABA | Alibaba | 1.7% | $5.39M | |
| DJCO | Daily Journal | 1.6% | $4.86M | |
| GOOGL | Alphabet | 0.9% | $2.82M | |
| SRG | Seritage Growth Properties | 0.5% | $1.54M | |
| AMR | Alpha Metallurgical | 0.3% | $900K | |
| CNR | Core Natural Resources | 0.2% | Added (+33%) | $749K |
Current Investment Strategy
Guy Spier's Aquamarine Fund maintained its ultra-concentrated, Buffett-inspired value approach in Q2 2025, allocating $310 million across just 14 positions with zero turnover, anchored by a dominant 68% weighting in financial services and payments giants Berkshire Hathaway, American Express, Mastercard, and Bank of America. The fund's unwavering buy-and-hold discipline—averaging 10-quarter holding periods—reflects Spier's conviction in high-quality franchises with durable competitive moats, supplemented by selective exposure to luxury (Ferrari), technology (Micron), and emerging markets (Alibaba).
New Investments
Aquamarine did not open any new positions during Q2 2025.
Added, Trimmed, and Exited
Added
Aquamarine Capital added to just one existing position: Core Natural Resources (CNR), increasing the stake by 2,640 shares (from 8,100 to 10,740 shares, a 33% increase).
What it means: Despite Core Natural Resources declining approximately 9.5% during the quarter, Guy Spier took advantage of the weakness to add meaningfully to this small position. This contrarian move exemplifies his value investing approach—buying more when prices fall rather than chasing winners. The willingness to average down on a natural resources holding suggests conviction in the underlying asset value and long-term fundamentals, even as the position remains relatively small compared to the fund's major holdings in financial services and technology companies.
Trimmed
Aquamarine Capital did not trim any positions during the quarter.
What it means: The absence of selling activity, even as several positions like Alibaba (BABA) fell 14% and Alpha Metallurgical (AMR) declined 10%, reflects Spier's disciplined long-term approach and reluctance to trade actively. This aligns with his philosophy of avoiding excessive trading and allowing quality companies to compound over decades, demonstrating patience even through short-term volatility.
Exited
Aquamarine Capital did not exit any positions during the quarter.
What it means: The decision to maintain all positions intact, despite the portfolio's overall slight decline of 0.05%, underscores Guy Spier's commitment to his highly concentrated, low-turnover strategy. This stability reflects confidence in the fund's existing holdings and suggests no fundamental deterioration in the investment theses for any of the portfolio companies, consistent with his focus on capital preservation and long-term compounding rather than tactical repositioning.
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.
