Current position

Guy Spier’s Berkshire Hathaway Inc Del (BRK/B) position

Reported position history, portfolio importance and verified filing changes from public SEC disclosures.

Aquamarine CapitalVerified through Q2 2026
Relationship snapshot

At a glance

The full verified relationship, including prior ownership episodes and exits where supported.

First reportedQ3 2022Earliest verified positive filing snapshot
Latest statusCurrent positionBased on the latest supported relationship state
Peak shares140.60KHighest verified quarter-end share count
Quarters reported16Verified quarters with shares above zero
What happened?

Aquamarine Capital first reported Berkshire Hathaway Inc Del in Q3 2022. The reported position was reduced across later filings. Aquamarine Capital currently reports 97.60K shares. The latest verified filing showed: No change.

Verified SEC history

Position over time

See the same verified relationship through reported shares, portfolio weight or reported value.

Metric

Gaps indicate periods that cannot be safely connected or where a verified corporate action changes the raw share scale. Stock price, when available, is market context and not a transaction price.

Key filing events

What changed

Latest filing plus the most meaningful reported changes. Unchanged quarters are collapsed by default.

Q2 2026
No change97.60K shares reported
Filing context

Quarter-end price $500.39 · Estimated holding basis $267.02

Q4 2025
Sold 30.6% of the position−43.00K shares · 97.60K shares remained
Filing context

Quarter-end price $502.65 · Estimated holding basis $267.02

Q4 2022
New position+140.60K shares · 140.60K shares reported
Filing context

Quarter-end price $308.90 · Estimated holding basis $267.02

12 unchanged quarters are collapsed by default.

Portfolio importance

How important is Berkshire Hathaway Inc Del in Aquamarine Capital’s reported portfolio?

Relative importance is measured only within the verified primary non-option reported portfolio for each quarter.

Current portfolio weight33.9%Q2 2026
Current rank#1of 7 reported positions
Peak portfolio weight34.6%Q1 2026
Best historical rank#1Q3 2022
At peak importanceQ1 2026
BRK/B
34.6%
Largest holding
34.6%
Cross-investor discovery

Who else owns Berkshire Hathaway Inc Del?

Also reported by 7 other tracked investors in their latest verified filings.

Bill GatesGates Foundation Trust
BRK/B21.4% of reported portfolio
Christopher BloomstranSemper Augustus Investments Group LLC
BRK/B15.5% of reported portfolio
Li LuHimalaya Capital Management
BRK/B15.0% of reported portfolio
Explore Berkshire Hathaway Inc Del across all tracked investors →
SEC evidence & methodology

SEC filing evidence

Market context and filing-derived values are kept separate from actual transaction prices, which 13F filings do not disclose.

Latest verified stock price$509.772026-09-18

Market context only; not an investor transaction price.

Latest filing quarter-end price$500.39Q2 2026

Derived from validated reported value and shares where supported.

Estimated holding basis$267.02Historical reference — not actual purchase price

Calculated from supported filing history.

Latest verified investor filingQ2 2026 · filed 2026-07-10
Open SEC filing ↗

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.