Aquamarine Zurich AGtracked
Open in PORT →Compare →Tear sheet →← all managersCIK 1953324
Reported long US book (13F) · Δ vs 2025-Q4 · methodology
Implied return what this book implies methodology →
As filed = each book applied at quarter-end (what it did) · As copyable = applied at the 45-day filing deadline (what a follower could have earned).
Computing…
Exposures · what it owns, by sector & size (2026-Q1)
By sector
By market cap
By region
By industry group GICS — finer than sector
| Industry group | Weight | Names |
|---|---|---|
| Unclassified | 57.89% | 3 |
| Commercial Services & Supplies | 23.48% | 2 |
| Banks | 14.53% | 1 |
| Media & Publishing | 4.10% | 1 |
Top holdings
| # | Ticker | Name | Sector | Weight |
|---|---|---|---|---|
| 1 | BRK.B | BERKSHIRE HATHAWAY INC | Financials | 34.57% |
| 2 | BRK.A | BERKSHIRE HATHAWAY INC DEL | Unclassified | 15.92% |
| 3 | MA | Mastercard Inc | Financials | 14.77% |
| 4 | AXP | AMERICAN EXPRESS CO | Financials | 14.53% |
| 5 | MCO | MOODYS CORP /DE/ | Financials | 8.71% |
| 6 | RACE | Ferrari N.V. | Consumer Discretionary | 7.40% |
| 7 | DJCO | DAILY JOURNAL CORP | Communication Services | 4.10% |
6/7 classified; unclassified names are still shown.
Sector allocation over time · how the sector mix & top names shifted each quarter
Sector allocation over 15 reported quarters, 2022-Q3 to 2026-Q1, 15 bands (top holdings within each sector). Latest quarter 2026-Q1: BRK.B 34.6%, BRK.A 15.9%, MA 14.8%, AXP 14.5%, MCO 8.7%. Use the arrow keys to read a quarter.
Sector is classified on each name's CURRENT fundamentals, not point-in-time — apparent sector drift can reflect the market re-rating a holding, not a manager trade. 13F is a lagged quarterly snapshot of long positions in US-listed securities only — foreign companies held via a US listing or ADR ARE included, but shares listed only on non-US exchanges (plus shorts, options and cash) are not. Latest quarter: 84.1% of the book is classified (unclassified names are still shown).
Style box · size × value-growth placement (2026-Q1), classified on today's fundamentals (not point-in-time) — load into PORT to overlay your own book
42% of book weight is classified — the grid represents that much of the book.
Classified: 42.1% of book weight (4/7 names) · unclassified 57.9%.
Contribution holdings-based, any period
Attribution lands once this book has priced history across the window. Try a longer period.
Holdings· 7 positions (2026-Q1) · largest first · Δ vs 2025-Q4
| # | Security | Shares | Value | Weight | Δ QoQ |
|---|---|---|---|---|---|
| 1 | BRK.BBERKSHIRE HATHAWAY INC DEL | 97,600 | $47M | 34.6% | HOLD |
| 2 | BRK.ABERKSHIRE HATHAWAY INC DEL | 30 | $22M | 15.9% | HOLD |
| 3 | MAMASTERCARD INCORPORATED | 40,000 | $20M | 14.8% | HOLD |
| 4 | AXPAMERICAN EXPRESS CO | 65,000 | $20M | 14.5% | HOLD |
| 5 | MCOMOODYS CORP | 27,000 | $12M | 8.7% | HOLD |
| 6 | RACEFERRARI N V | 30,000 | $10M | 7.4% | HOLD |
| 7 | DJCODAILY JOURNAL CORP | 11,500 | $6M | 4.1% | HOLD |
Position trends· top 7 holdings · shares held over 6 quarters
| Security | 2024-Q4 | 2025-Q1 | 2025-Q2 | 2025-Q3 | 2025-Q4 | 2026-Q1 | Latest value |
|---|---|---|---|---|---|---|---|
| BRK.BBERKSHIRE HATHAWAY INC DEL | 141K | 141K | 141K | 141K | 98K | 98K | $47M |
| BRK/ABERKSHIRE HATHAWAY INC DEL | 30 | 30 | 30 | 30 | 30 | 30 | $22M |
| MAMASTERCARD INCORPORATED | 66K | 66K | 66K | 66K | 40K | 40K | $20M |
| AXPAMERICAN EXPRESS CO | 210K | 210K | 210K | 210K | 65K | 65K | $20M |
| MCOMOODYS CORP | 27K | 27K | 27K | 27K | 27K | 27K | $12M |
| RACEFERRARI N V | 60K | 60K | 60K | 60K | 30K | 30K | $10M |
| DJCODAILY JOURNAL CORP | 12K | 12K | 12K | 12K | 12K | 12K | $6M |
Green = added, red = trimmed, grey = held; a dash is a quarter with no 13F on file — a gap, not an exit.
Related· where to look next
Where this firm's principals came from, and what its alumni went on to found.
joins filed 13F data only — no style, strategy or performance similarity is claimed · 13F 2026-Q1
Also hold BRK.B — other Section 13(f) filers reporting a long position in this book's largest tickered holding for 2026-Q1. Lagged quarterly filings (up to 45 days after quarter-end); “% of shares out” is omitted where the reported share count can't carry it.
Filers outside the free window show locked, not hidden.