Aquamarine Capital 13F, Q3 2025
Guy Spier · quarter ending 30 September 2025 · filed 20 October 2025 · SEC CIK 1953324
Common stock only: shares the fund reported owning at the quarter end, valued as filed.
Largest positions, Q3 2025
Weights are against the whole filed book. Changes are in shares held, against the Q2 2025 filing.
| Company | Ticker | Value | % of book | vs Q2 2025 |
|---|---|---|---|---|
| BERKSHIRE HATHAWAY INC DEL | BRK/B | $70.69M | 22.3% | unchanged |
| AMERICAN EXPRESS CO | AXP | $69.75M | 22.0% | unchanged |
| BANK AMERICA CORP | BAC | $39.61M | 12.5% | unchanged |
| MASTERCARD INCORPORATED | MA | $37.40M | 11.8% | unchanged |
| FERRARI N V | $28.98M | 9.1% | unchanged | |
| BERKSHIRE HATHAWAY INC DEL | BRK/A | $22.63M | 7.1% | unchanged |
| MICRON TECHNOLOGY INC | MU | $13.39M | 4.2% | -60% shares |
| MOODYS CORP | MCO | $12.87M | 4.0% | unchanged |
| ALIBABA GROUP HLDG LTD | BABA | $8.49M | 2.7% | unchanged |
| DAILY JOURNAL CORP | DJCO | $5.35M | 1.7% | unchanged |
| ALPHABET INC | GOOGL | $3.89M | 1.2% | unchanged |
| SERITAGE GROWTH PPTYS | SRG | $2.13M | 0.7% | unchanged |
| ALPHA METALLURGICAL RESOUR I | AMR | $1.31M | 0.4% | unchanged |
| CORE NATURAL RESOURCES INC | CNR | $897.0K | 0.3% | unchanged |
What changed since Q2 2025
Against the Q2 2025 filing, Aquamarine Capital opened 0 new positions, added to 0, trimmed 1, left 13 unchanged and exited 0. Every position is compared, matched on its CUSIP; a change of 2% or less in shares counts as unchanged.
New positions
No new positions this quarter.
Exited
Nothing from the previous filing was sold outright.
Added to
No position was increased by more than 2%.
Trimmed
- MU-60%$13.39M
Other quarters
Source: SEC Form 13F-HR, accession 0001953324-25-000007, filed by Aquamarine Zurich AG. Values are as filed and cover US-listed positions only; a 13F does not show short positions or holdings outside the US. A 13F may be filed up to 45 days after the quarter ends, so the fund may have traded since. Educational information, not financial advice.