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Built from publicly disclosed institutional and insider activity. Informational purposes only - not investment advice.OpenStocks · v0.1
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  1. Home/
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  3. Guy Spier (Aquamarine Zurich)
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Guy Spier

Aquamarine Zurich
Share
  • Hedge Fund · CIK 0001953324
  • Financials-Focused
  • Highly Concentrated
  • Boutique

Guy Spier runs Aquamarine Zurich, a hedge fund overseeing $135K in disclosed equity holdings (SEC CIK 0001953324). The latest portfolio (2026Q1) discloses 7 positions across 2 sectors, with the largest positions in BRK.B, BRK.A and MA. On a mark-to-market basis the tracked portfolio has returned 53.6% since 2024Q2. OpenStocks tracks 8 consecutive quarterly snapshots for this manager — every position change, new entry, and exit is logged below.

Track Guy's filingsView holdings↓
Portfolio
$135.3K
Positions
7
Quarter
2026Q1
Filings tracked
8
Since filing+53.6%Full performance →
Quarter
2026Q12025Q42025Q32025Q22025Q12024Q42024Q32024Q2

Holdings

Sorted by value · 2025Q4
7 positions
1
B
BRK.BBERKSHIRE HATHAWAY INC DEL
33.25%
of portfolio
Number of shares
97,600 sh
Holdings current value
$49.1K
Avg closing price
$406.80
+15.7%
Last action
Trimmed 30.6%
2025Q4
Current $470.55
2
A
AXPAMERICAN EXPRESS CO
Financial Services·Credit Services
16.30%
of portfolio
Number of shares
65,000 sh
Holdings current value
$24.0K
Avg closing price
$231.55
+37.6%
Last action
Trimmed 69.0%
2025Q4
Current $318.55
3
M
MAMASTERCARD INCORPORATED
Financial Services·Credit Services
15.48%
of portfolio
Number of shares
40,000 sh
Holdings current value
$22.8K
Avg closing price
$441.16
+13.9%
Last action
Trimmed 39.2%
2025Q4
Current $502.38
4
B
BRK.ABERKSHIRE HATHAWAY INC DEL
15.35%
of portfolio
Number of shares
30 sh
Holdings current value
$22.6K
Avg closing price
$612233
+15.3%
Last action
—
Current $706165
5
M
MCOMOODYS CORP
Financial Services·Financial Data & Stock Exchanges
9.35%
of portfolio
Number of shares
27,000 sh
Holdings current value
$13.8K
Avg closing price
$420.93
+7.5%
Last action
—
Current $452.35
6
N
N3167Y103FERRARI N V
6.48%
of portfolio
Number of shares
30,000 sh
Holdings current value
$9.6K
Avg closing price
$407.85
Last action
Trimmed 50.0%
2025Q4
Current —
7
D
DJCODAILY JOURNAL CORP
Technology·Software - Application
3.80%
of portfolio
Number of shares
11,500 sh
Holdings current value
$5.6K
Avg closing price
$394.52
+34.2%
Last action
—
Current $529.50

Portfolio heatmap

Box size = % of portfolio · color = return since filing
BRK.B
33.25% · +93513.2%
AXP
16.30% · +86005.3%
MA
15.48% · +87901.8%
BRK.A
15.35% · +93456.6%
MCO
9.35% · +88448.2%
FERRARI N V
6.48%
DJCO
3.80% · +108559.0%

Sector exposure

Share of dollar value across the latest reported portfolio. Unclassified positions excluded.
  • Financial Services3 pos$61K91.5%
  • Technology1 pos$6K8.5%
(55.1% unclassified, excluded from %)