Current position

Guy Spier’s Mastercard (MA) 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 shares65.75KHighest verified quarter-end share count
Quarters reported16Verified quarters with shares above zero
What happened?

Aquamarine Capital first reported Mastercard in Q3 2022. The reported position was reduced across later filings. Aquamarine Capital currently reports 40.00K 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 change40.00K shares reported
Filing context

Quarter-end price $513.60 · Estimated holding basis $284.33

Q4 2025
Sold 39.2% of the position−25.75K shares · 40.00K shares remained
Filing context

Quarter-end price $570.88 · Estimated holding basis $284.33

Q4 2022
New position+65.75K shares · 65.75K shares reported
Filing context

Quarter-end price $347.73 · Estimated holding basis $284.33

12 unchanged quarters are collapsed by default.

Portfolio importance

How important is Mastercard in Aquamarine Capital’s reported portfolio?

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

Current portfolio weight14.3%Q2 2026
Current rank#4of 7 reported positions
Peak portfolio weight15.5%Q4 2025
Best historical rank#3Q1 2023
At peak importanceQ4 2025
MA
15.5%
Largest holding
33.3%
Cross-investor discovery

Who else owns Mastercard?

Also reported by 8 other tracked investors in their latest verified filings.

Chuck AkreAkre Capital Management
MA20.0% of reported portfolio
Dev KantesariaValley Forge Capital Management
MA17.6% of reported portfolio
Tom RussoGardner Russo & Quinn · formerly Gardner Russo & Gardner
MA8.8% of reported portfolio
Explore Mastercard 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$565.242026-09-18

Market context only; not an investor transaction price.

Latest filing quarter-end price$513.60Q2 2026

Derived from validated reported value and shares where supported.

Estimated holding basis$284.33Historical reference — not actual purchase price

Calculated from supported filing history.

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

View Mastercard stock page →

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.