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High-profile investor tracker

Guy Spier Portfolio

Aquamarine Capital Holdings

A filing-based view of Aquamarine Capital’s publicly disclosed U.S.-listed equity holdings — with portfolio concentration, quarter-over-quarter changes and verified quarterly SEC history.

This tracker follows the current Aquamarine Zurich AG Form 13F filer and bridges its verified history to the former Aquamarine Capital Management LLC filer. It does not represent Guy Spier’s personal brokerage account or the fund’s complete global portfolio.

Confirmed SEC snapshot

$144.1K

Reported 13F value · Q2 2026

713F entries
2026-07-10filing date
13F-HRsource filing
16verified quarters

Portfolio

BERKSHIRE HATHAWAY INC DELBRK/B
$48.8K
33.9%
+100,747.7%Est. vs filing basis
Unchanged
Reported shares97,600
Current price$507.00
SEC reference price$0.50
Estimated filing-based basis$0.50
Position historySEC quarter-end observations
Q2 2026
Unchanged
SEC ref. $0.50Est. basis $0.50
Q1 2026
Unchanged
SEC ref. $0.48Est. basis $0.50
Q4 2025
Reduced 30.6%-43,000 reported shares
SEC ref. $0.50Est. basis $0.50
Q4 2024
Unchanged
SEC ref. $0.45Est. basis $267.02
Q3 2024
Unchanged
SEC ref. $0.46Est. basis $267.02
Q2 2024
Unchanged
SEC ref. $0.41Est. basis $267.02
Q1 2024
Unchanged
SEC ref. $0.42Est. basis $267.02
Q4 2023
Unchanged
SEC ref. $0.36Est. basis $267.02
Q3 2023
Unchanged
SEC ref. $0.35Est. basis $267.02
Q2 2023
Unchanged
SEC ref. $0.34Est. basis $267.02
Q1 2023
Unchanged
SEC ref. $0.31Est. basis $267.02
Q4 2022
Unchanged
SEC ref. $0.31Est. basis $267.02
BERKSHIRE HATHAWAY INC DELBRK/A
$22.5K
15.6%
+100,834.1%Est. vs filing basis
Unchanged
Reported shares30
Current price$761,245.00
SEC reference price$748.87
Estimated filing-based basis$754.20
Position historySEC quarter-end observations
Q2 2026
Unchanged
SEC ref. $748.87Est. basis $754.20
Q1 2026
Unchanged
SEC ref. $718.13Est. basis $754.20
Q4 2025
Unchanged
SEC ref. $754.80Est. basis $754.20
Q4 2024
Unchanged
SEC ref. $680.93Est. basis $406,466.67
Q3 2024
Unchanged
SEC ref. $691.17Est. basis $406,466.67
Q2 2024
Unchanged
SEC ref. $612.23Est. basis $406,466.67
Q1 2024
Unchanged
SEC ref. $634.43Est. basis $406,466.67
Q4 2023
Unchanged
SEC ref. $542.63Est. basis $406,466.67
Q3 2023
Unchanged
SEC ref. $531.47Est. basis $406,466.67
Q2 2023
Unchanged
SEC ref. $517.80Est. basis $406,466.67
Q1 2023
Unchanged
SEC ref. $465.60Est. basis $406,466.67
Q4 2022
Unchanged
SEC ref. $468.70Est. basis $406,466.67
AMERICAN EXPRESS CO AXP
$22.0K
15.3%
+96,452.3%Est. vs filing basis
Unchanged
Reported shares65,000
Current price$320.71
SEC reference price$0.34
Estimated filing-based basis$0.33
Position historySEC quarter-end observations
Q2 2026
Unchanged
SEC ref. $0.34Est. basis $0.33
Q1 2026
Unchanged
SEC ref. $0.30Est. basis $0.33
Q4 2025
Reduced 69.0%-145,000 reported shares
SEC ref. $0.37Est. basis $0.33
Q4 2024
Unchanged
SEC ref. $0.30Est. basis $134.91
Q3 2024
Unchanged
SEC ref. $0.27Est. basis $134.91
Q2 2024
Unchanged
SEC ref. $0.23Est. basis $134.91
Q1 2024
Unchanged
SEC ref. $0.23Est. basis $134.91
Q4 2023
Unchanged
SEC ref. $0.19Est. basis $134.91
Q3 2023
Unchanged
SEC ref. $0.15Est. basis $134.91
Q2 2023
Unchanged
SEC ref. $0.17Est. basis $134.91
Q1 2023
Unchanged
SEC ref. $0.16Est. basis $134.91
Q4 2022
Unchanged
SEC ref. $0.15Est. basis $134.91
MASTERCARD INCORPORATEDMA
$20.5K
14.3%
+99,295.9%Est. vs filing basis
Unchanged
Reported shares40,000
Current price$565.37
SEC reference price$0.51
Estimated filing-based basis$0.57
Position historySEC quarter-end observations
Q2 2026
Unchanged
SEC ref. $0.51Est. basis $0.57
Q1 2026
Unchanged
SEC ref. $0.50Est. basis $0.57
Q4 2025
Reduced 39.2%-25,750 reported shares
SEC ref. $0.57Est. basis $0.57
Q4 2024
Unchanged
SEC ref. $0.53Est. basis $284.33
Q3 2024
Unchanged
SEC ref. $0.49Est. basis $284.33
Q2 2024
Unchanged
SEC ref. $0.44Est. basis $284.33
Q1 2024
Unchanged
SEC ref. $0.48Est. basis $284.33
Q4 2023
Unchanged
SEC ref. $0.43Est. basis $284.33
Q3 2023
Unchanged
SEC ref. $0.40Est. basis $284.33
Q2 2023
Unchanged
SEC ref. $0.39Est. basis $284.33
Q1 2023
Unchanged
SEC ref. $0.36Est. basis $284.33
Q4 2022
Unchanged
SEC ref. $0.35Est. basis $284.33
MOODYS CORPMCO
$12.2K
8.5%
+97,985.7%Est. vs filing basis
Unchanged
Reported shares27,000
Current price$467.36
SEC reference price$0.45
Estimated filing-based basis$0.48
Position historySEC quarter-end observations
Q2 2026
Unchanged
SEC ref. $0.45Est. basis $0.48
Q1 2026
Unchanged
SEC ref. $0.44Est. basis $0.48
Q4 2025
Unchanged
SEC ref. $0.51Est. basis $0.48
Q4 2024
Unchanged
SEC ref. $0.47Est. basis $243.11
Q3 2024
Unchanged
SEC ref. $0.47Est. basis $243.11
Q2 2024
Unchanged
SEC ref. $0.42Est. basis $243.11
Q1 2024
Unchanged
SEC ref. $0.39Est. basis $243.11
Q4 2023
Unchanged
SEC ref. $0.39Est. basis $243.11
Q3 2023
Unchanged
SEC ref. $0.32Est. basis $243.11
Q2 2023
Unchanged
SEC ref. $0.35Est. basis $243.11
Q1 2023
Unchanged
SEC ref. $0.31Est. basis $243.11
Q4 2022
Unchanged
SEC ref. $0.28Est. basis $243.11
FERRARI N V
$11.1K
7.7%
—Est. vs filing basis
Unchanged
Reported shares30,000
SEC reference price$0.37
Estimated filing-based basis$0.48
Position historySEC quarter-end observations
Q2 2026
Unchanged
SEC ref. $0.37Est. basis $0.48
Q1 2026
Unchanged
SEC ref. $0.33Est. basis $0.48
Q4 2025
Reduced 50.0%-30,000 reported shares
SEC ref. $0.32Est. basis $0.48
Q4 2024
Unchanged
SEC ref. $0.41Est. basis $187.90
Q3 2024
Unchanged
SEC ref. $0.47Est. basis $187.90
Q2 2024
Unchanged
SEC ref. $0.41Est. basis $187.90
Q1 2024
Reduced 25.0%-20,000 reported shares
SEC ref. $0.44Est. basis $187.90
Q4 2023
Unchanged
SEC ref. $0.34Est. basis $187.90
Q3 2023
Unchanged
SEC ref. $0.30Est. basis $187.90
Q2 2023
Unchanged
SEC ref. $0.33Est. basis $187.90
Q1 2023
Unchanged
SEC ref. $0.27Est. basis $187.90
Q4 2022
Unchanged
SEC ref. $0.21Est. basis $187.90
DAILY JOURNAL CORPDJCO
$6.9K
4.8%
+139,151.3%Est. vs filing basis
Unchanged
Reported shares11,500
Current price$647.70
SEC reference price$0.60
Estimated filing-based basis$0.47
Position historySEC quarter-end observations
Q2 2026
Unchanged
SEC ref. $0.60Est. basis $0.47
Q1 2026
Unchanged
SEC ref. $0.48Est. basis $0.47
Q4 2025
Unchanged
SEC ref. $0.49Est. basis $0.47
Q4 2024
Unchanged
SEC ref. $0.57Est. basis $256.35
Q3 2024
Unchanged
SEC ref. $0.49Est. basis $256.35
Q2 2024
Unchanged
SEC ref. $0.39Est. basis $256.35
Q1 2024
Unchanged
SEC ref. $0.36Est. basis $256.35
Q4 2023
Unchanged
SEC ref. $0.34Est. basis $256.35
Q3 2023
Unchanged
SEC ref. $0.29Est. basis $256.35
Q2 2023
Unchanged
SEC ref. $0.29Est. basis $256.35
Q1 2023
Unchanged
SEC ref. $0.28Est. basis $256.35
Q4 2022
Unchanged
SEC ref. $0.25Est. basis $256.35

Performance

Estimated 1Y performanceFiling-based estimate

+6.11%

Coverage 78% Partial estimate

Quarterly performanceBackend-published quarter legs within the 1Y estimate
2025-09-30+8.91%
2025-12-31-0.24%
2026-03-31-8.30%
2026-06-30+6.50%

Displayed legs are backend-ready filing-based estimates. They explain the path of the published 1Y result and are not summed or compounded in the browser.

MethodologyMIL_SEC_PERFORMANCE_V2_EXIT_AWARE_M2M
What this measures

Estimated return from standardized SEC-reported portfolio observations using the approved filing-based methodology. It is not an actual transaction-level or realized investor return.

Portfolio history

Q2 2026
$144.1K
7 positions
Q1 2026
$135.3K
7 positions
Q4 2025
$147.5K
7 positions
Q3 2025
$317.4K
14 positions
Q2 2025
$309.8K
14 positions

Methodology

1. Start with SEC filings

Official Form 13F filings and the canonical MarketInsiderLab filing record are authoritative. Unsupported or unverified data is withheld.

2. Use the verified filing denominator

Portfolio weights use the verified full filing total. Security identity and corporate-action continuity are reconciled before publication.

3. Compare verified quarter-end snapshots

Changes describe differences between verified SEC-reported quarter-end positions. They are not presented as exact buys, sells, trade dates, or execution prices.

4. Keep estimates clearly separated

Estimated filing-based basis and filing-based performance are backend-calculated research estimates, not actual execution prices or audited fund returns.

1-year performance is published only when four consecutive quarterly estimates pass QA and the weakest quarterly leg has at least 70% measurable coverage. Coverage of 90% or more is labeled High coverage; 70–89.9% is labeled Partial estimate. Lower-coverage estimates are withheld.

Guy Spier Portfolio FAQ

How to interpret Aquamarine Capital’s delayed SEC disclosures.

What does this page track?
It tracks the publicly disclosed U.S.-listed Form 13F positions associated with Guy Spier’s Aquamarine filing lineage. It is not his personal account or Aquamarine’s complete global portfolio.
Why are two SEC CIKs used?
The verified five-year series moves from Aquamarine Capital Management LLC’s CIK through Q2 2022 to Aquamarine Zurich AG’s CIK beginning in Q3 2022. The tracker preserves that disclosed continuity while monitoring the current filer.
Why are Berkshire’s share classes combined?
The SEC reports Class A and Class B separately. Company-level ranking sums their reported values; the chart converts Class A shares to BRK.B-equivalent units at 1,500 Class B shares per Class A share while preserving both raw CUSIPs.
Why are ordinary shares and options shown separately?
Put and call entries are excluded from ordinary-share rankings, weights and chart selection, displayed in their own section, and still included in the complete filing denominator. The latest Aquamarine filing reported no options.
Does Form 13F show exact trade dates?
No. It shows reportable positions at quarter-end and is filed later. Changes are inferred by comparing consecutive reports.
MarketInsiderLab tracks what public filings actually show.

Research and context — not a recommendation to copy any investor’s trades.

Explore investor portfolios →

Guy Spier Portfolio FAQ

How to interpret Aquamarine Capital’s delayed SEC disclosures.

What does this page track?
It tracks the publicly disclosed U.S.-listed Form 13F positions associated with Guy Spier’s Aquamarine filing lineage. It is not his personal account or Aquamarine’s complete global portfolio.
Why are two SEC CIKs used?
The verified five-year series moves from Aquamarine Capital Management LLC’s CIK through Q2 2022 to Aquamarine Zurich AG’s CIK beginning in Q3 2022. The tracker preserves that disclosed continuity while monitoring the current filer.
Why are Berkshire’s share classes combined?
The SEC reports Class A and Class B separately. Company-level ranking sums their reported values; the chart converts Class A shares to BRK.B-equivalent units at 1,500 Class B shares per Class A share while preserving both raw CUSIPs.
Why are ordinary shares and options shown separately?
Put and call entries are excluded from ordinary-share rankings, weights and chart selection, displayed in their own section, and still included in the complete filing denominator. The latest Aquamarine filing reported no options.
Does Form 13F show exact trade dates?
No. It shows reportable positions at quarter-end and is filed later. Changes are inferred by comparing consecutive reports.
MarketInsiderLab tracks what public filings actually show.Research and context — not a recommendation to copy any investor’s trades.
Explore investor portfolios →