Guy Spier Aquamarine Zurich
Guy Spier is the founder of Aquamarine Capital and a well-known advocate of value investing in the Buffett-Munger tradition. He is the author of The Education of a Value Investor and is known for a patient, checklist-oriented process and limited portfolio turnover. Spier’s public holdings and writings attract individual investors who study behavioral discipline as much as stock picking.
Top Buys
Top Sells
| Rank | Stock | Value |
|---|---|---|
| 1 |
Micron Technology
MU
|
+$15.4M |
Sector Composition
| Rank | Sector | Weight |
|---|---|---|
| 1 | Financials | 79.7% |
| 2 | Consumer Discretionary | 11.81% |
| 3 | Technology | 5.9% |
| 4 | Communication Services | 1.23% |
| 5 | Real Estate | 0.67% |
| Name | Market Value | Portfolio Weight | Shares or Principal |
Change in Stake | Capital Flow | |
|---|---|---|---|---|---|---|
1
Berkshire Hathaway Class B
BRK.B
$1.06T
| $70.7M | 22.27% |
140,600
| – | – |
|
2
American Express
AXP
$227B
| $69.8M | 21.98% |
210,000
| – | – |
|
3
Bank of America
BAC
$431B
| $39.6M | 12.48% |
767,845
| – | – |
|
4
Mastercard
MA
$509B
| $37.4M | 11.78% |
65,750
| – | – |
|
5
Ferrari
RACE
$76.7B
| $29M | 9.13% |
60,000
| – | – |
|
|
6
Berkshire Hathaway Class A
BRK.A
$1.06T
| $22.6M | 7.13% |
30
| – | – |
|
|
7
Micron Technology
MU
$1.09T
| $13.4M | 4.22% |
80,000
-120,000
| -60% | -$15.4M |
|
8
Moody's
MCO
$87.2B
| $12.9M | 4.05% |
27,000
| – | – |
|
9
Alibaba
BABA
$286B
| $8.49M | 2.68% |
47,500
| – | – |
|
10
Daily Journal
DJCO
$827M
| $5.35M | 1.69% |
11,500
| – | – |
|
11
Alphabet (Google) Class A
GOOGL
$4.22T
| $3.89M | 1.23% |
16,000
| – | – |
|
|
SRG
12
Seritage Growth Properties
SRG
$120M
| $2.13M | 0.67% |
500,000
| – | – |
|
13
Alpha Metallurgical Resources
AMR
$2.66B
| $1.31M | 0.41% |
8,000
| – | – |
|
|
CNR
14
Core Natural Resources Inc
CNR
$4.72B
| $897K | 0.28% |
10,740
| – | – |
|
Similar funds
Guy Spier's Q3 2025 Portfolio in Review
As of Q3 2025, Guy Spier held 14 positions worth $317M, up 2.4% from $310M the previous quarter. Its ten largest holdings account for 97% of the portfolio.
Guy Spier withdrew a net $15.4M in Q3 2025, reducing 1 holding. Its largest reduction was Micron Technology, cutting an estimated $15.4M.
By sector, the portfolio is most concentrated in Financials at 80% of assets, up from 79% a quarter earlier, followed by Consumer Discretionary and Technology.
- Guy Spier's biggest Q3 2025 reduction was Micron Technology, cutting an estimated $15.4M.
- Guy Spier's ten largest holdings make up 97% of its $317M portfolio in Q3 2025.
- Guy Spier opened 0 new positions and closed 0 in Q3 2025.
- Guy Spier's portfolio value rose 2.4% quarter-over-quarter to $317M.
Based on Aquamarine Zurich's 13F filing for Q3 2025, filed 20 Oct 2025.