Guy Spier's Aquamarine Capital holds 30 shares of Berkshire Hathaway Inc (BRK-A) worth about $22.4M as of September 30, 2026, according to the 13F-HR filed with the SEC on November 10, 2026. The position is 15.53% of the reported portfolio, the 2nd largest of 7 stock positions. Guy Spier left the share count unchanged from the prior quarter.
What did the 2026 Q3 filing report for BRK-A?
As of September 30, 2026, from the 13F-HR filed November 10, 2026.
| Value | |
|---|---|
| Portfolio weight | 15.53% |
| Shares | 30 |
| Reported value | $22.4M |
| Rank in portfolio | 2nd of 7 |
| Largest holding | BRK-B at 33.66% |
| Top three holdings | 64.49% of the book |
| Change this quarter | unchanged |
How concentrated is Guy Spier in BRK-A?
BRK-A at 15.53% is 1.1 times the average stock position in the Guy Spier portfolio, which is 14%. The largest holding is BRK-B at 33.66%. The three largest stocks together are 64.49% of the reported book. A quarter earlier BRK-A was 15.59% of the book.
Where does BRK-A sit in the Guy Spier portfolio?
BRK-A ranks 2nd of 7 stock positions in the Guy Spier portfolio at 15.53%, about the fund's average stock position of 14%. Across the 2026 Q3 portfolio, Guy Spier reported 7 stock positions, with no position opened or closed. The total portfolio value is about $144M, little changed from the prior quarter.
How long has Guy Spier held BRK-A?
Guy Spier first reported BRK-A in the quarter ended December 31, 2014. The weight peaked at 15.92% in 2026 Q1. The share count was unchanged the quarter before. Every reported trade is on the Guy Spier BRK-A trade history page.
Did other funds buy or sell BRK-A in 2026 Q3?
Among the other tracked funds that had filed for 2026 Q3 as of November 10, 2026, 2 hold BRK-A. Every tracked holder of BRK-A is on the BRK-A ownership page.
FAQ
What share of the Guy Spier portfolio is BRK-A?
BRK-A is 15.53% of the Guy Spier portfolio as of 2026 Q3, the 2nd largest of 7 stock positions.
What is the BRK-A stake of Guy Spier worth?
Guy Spier holds 30 shares of BRK-A, worth about $22.4M at September 30, 2026 prices, 15.53% of the reported portfolio.
What are the largest holdings of Guy Spier?
The largest stock positions of Guy Spier as of 2026 Q3 are BRK-B (33.66%), BRK-A (15.53%) and MA (15.29%), together 64.49% of the book.
Did Guy Spier's Aquamarine Capital change its BRK-A position in 2026 Q3?
Guy Spier left the share count unchanged from the prior quarter.