Aquamarine Capital
13F Holdings and Portfolio Analysis
Guy Spier 2025 Q4 13F holdings, quarterly changes, portfolio value trend and position weight distribution.
Aquamarine Capital Overview
Aquamarine Capital held 7 stocks in 2025 Q4, with total market value around $0.15B.
Aquamarine Capital's top five holdings in 2025 Q4: BERKSHIRE HATHAWAY INC DEL CL B NEW(BRK.B) 33.25%, American Express Company(AXP) 16.30%, Mastercard Incorporated(MA) 15.48%, BERKSHIRE HATHAWAY INC CL A(BRK.A) 15.35%, Moody's Corporation(MCO) 9.35%.
- Portfolio Value
- $0.15B
- Current Holdings
- 7 stocks
- New / Increased
- 0 / 0
- Reduced / Exited
- 4 / 7
Current Holdings
| 1 | BERKSHIRE HATHAWAY INC DEL CL B NEWBRK.B | 0.05 | 33.25% | 0.10 -30.58% | $502.65 | $470.25 -6.45% | $162.98 | -0.04 | 6.75 | +$0.03B+188.53% | Reduced |
| 2 | American Express CompanyAXP | 0.02 | 16.30% | 0.07 -69.05% | $369.95 | $345.73 -6.55% | $74.08 | -0.14 | 6.75 | +$0.02B+366.68% | Reduced |
| 3 | Mastercard IncorporatedMA | 0.02 | 15.48% | 0.04 -39.16% | $570.88 | $490.28 -14.12% | $86.16 | -0.03 | 8.75 | +$0.02B+469.04% | Reduced |
| 4 | BERKSHIRE HATHAWAY INC CL ABRK.A | 0.02 | 15.35% | 0.00 - | $754800.00 | $705400.23 -6.54% | $244133.33 | 0.00 | 6.75 | +$0.01B+188.94% | Held |
| 5 | Moody's CorporationMCO | 0.01 | 9.35% | 0.03 - | $510.85 | $459.29 -10.09% | $109.76 | 0.00 | 7.50 | +$0.01B+318.45% | Held |
| 6 | FERRARI N V COMRACE | 0.01 | 6.48% | 0.03 -50.00% | $318.70 | - | $41.53 | -0.03 | 7.50 | +$0.01B+667.30% | Reduced |
| 7 | DAILY JOURNAL CORPDJCO | 0.01 | 3.80% | 0.01 - | $487.30 | - | $338.52 | 0.00 | 2.25 | +$0.00B+43.95% | Held |
Showing 1-7 of 7
"Holding Period (yrs)" is the latest uninterrupted holding duration, calculated by dividing continuous reported quarters by 4.
Cost basis is an estimate and can differ materially from the actual cost, especially in edge cases.
Cost basis estimate: from the latest uninterrupted holding period, new or increased shares are added to the cost pool at the report price; reductions remove shares at the then-average cost. Example: buy 100 shares at $10 in Q1 and add 50 shares at $16 in Q2, estimated cost basis is (100 x 10 + 50 x 16) / 150 = $12 per share.
Return shows estimated dollar return on top and percentage return below. It uses current price when available, otherwise report price.
Exited Holdings
Stocks no longer disclosed in the current 13F portfolio for 2025 Q4.
| 1 | Bank of America CorporationBAC | 0.77 | 6.50 | $23.37 | $55.00 | +$0.02B+135.33% |
| 2 | Micron Technology, Inc.MU | 0.08 | 3.75 | $55.78 | $167.32 | +$0.01B+199.96% |
| 3 | Alibaba Group Holding LimitedBABA | 0.05 | 2.00 | $226.78 | $146.58 | -$0.00B-35.36% |
| 4 | ALPHABET INC CAP STK CL AGOOGL | 0.02 | 3.00 | $70.88 | $313.00 | +$0.00B+341.62% |
| 5 | SERITAGE GROWTH PROP- ASRG | 0.50 | 7.25 | $37.55 | $4.25 | -$0.02B-88.68% |
| 6 | ALPHA METALLURGICAL RESOUR I COMAMR | 0.01 | 0.75 | $125.25 | $199.88 | +$0.00B+59.58% |
| 7 | CORE NATURAL RESOURCES INC COM SHSCNR | 0.01 | 0.75 | $77.09 | $83.52 | +$0.00B+8.33% |
Showing 1-7 of 7
Exited holdings are stocks disclosed in the previous report period but no longer disclosed in the current 13F portfolio.
"Holding Period (yrs)" is the latest uninterrupted holding duration, calculated by dividing continuous reported quarters by 4.
Cost basis uses the same weighted cost-pool method as current holdings. Estimated exit price uses the current report period weighted report price when available, otherwise the previous report price; it does not represent the actual sale price.
Exit return shows estimated dollar return on top and percentage return below.
Portfolio Visuals
Track portfolio value, position weights and Top 10 history.