Guy Spier's Aquamarine Capital holds 97.6K shares of Berkshire Hathaway Inc (BRK-B) worth about $48.8M as of June 30, 2026, according to the 13F-HR filed with the SEC on July 10, 2026. The position is 33.89% of the reported portfolio, the largest of 7 stock positions. Guy Spier left the share count unchanged from the prior quarter.
What did the 2026 Q2 filing report for BRK-B?
As of June 30, 2026, from the 13F-HR filed July 10, 2026.
| Value | |
|---|---|
| Portfolio weight | 33.89% |
| Shares | 97.6K |
| Reported value | $48.8M |
| Rank in portfolio | 1st of 7 |
| Next largest holding | BRK-A at 15.59% |
| Top three holdings | 64.74% of the book |
| Change this quarter | unchanged |
How concentrated is Guy Spier in BRK-B?
BRK-B at 33.89% is 2.4 times the average stock position in the Guy Spier portfolio, which is 14%. The next largest holding is BRK-A at 15.59%. The three largest stocks together are 64.74% of the reported book. A quarter earlier BRK-B was 34.57% of the book.
Where does BRK-B sit in the Guy Spier portfolio?
BRK-B is the largest of 7 stock positions in the Guy Spier portfolio at 33.89%, above the fund's average stock position of 14%. Across the 2026 Q2 portfolio, Guy Spier reported 7 stock positions, with no position opened or closed. The total portfolio value is about $144.1M, up 6% from the prior quarter.
How long has Guy Spier held BRK-B?
Guy Spier first reported BRK-B in the quarter ended December 31, 2014. The weight peaked at 34.57% in 2026 Q1. The share count was unchanged the quarter before. Every reported trade is on the Guy Spier BRK-B trade history page.
Did other funds buy or sell BRK-B in 2026 Q2?
Among the other tracked funds that had filed for 2026 Q2 as of July 10, 2026, 18 hold BRK-B. One other tracked fund sold out of it. The largest buyers of BRK-B this quarter were Duan Yongping, Donald Yacktman and Li Lu. The largest sellers were Bill Gates, Thomas Russo and Francois Rochon. Every tracked holder of BRK-B is on the BRK-B ownership page.
FAQ
What share of the Guy Spier portfolio is BRK-B?
BRK-B is 33.89% of the Guy Spier portfolio as of 2026 Q2, the largest of 7 stock positions.
What is the BRK-B stake of Guy Spier worth?
Guy Spier holds 97.6K shares of BRK-B, worth about $48.8M at June 30, 2026 prices, 33.89% of the reported portfolio.
What are the largest holdings of Guy Spier?
The largest stock positions of Guy Spier as of 2026 Q2 are BRK-B (33.89%), BRK-A (15.59%) and AXP (15.26%), together 64.74% of the book.
Did Guy Spier's Aquamarine Capital change its BRK-B position in 2026 Q2?
Guy Spier left the share count unchanged from the prior quarter.