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Guy Spier - Aquamarine Capital Management
34 trades  ·  27 closed  ·  7 open  ·  Win rate: 52.9%  ·  Avg return: +93.4%  ·  Median return: +12.3%
1 of these positions have a value-scale error in the underlying SEC filing (an entry or exit price ≥25× off the rest of the holding), so their return is unreliable. They are marked data error below and excluded from the stats above, but their quarter-by-quarter filing history is still attached — open History on any row to see it exactly as filed.
Stock Entry
Quarter
Entry
Price
Exit
Quarter
Exit / Current
Price
Return Status Filings
RACE - Ferrari N.V.
Q1 2016 $41.53 Open $369.16 +788.90% Open History
MA - Mastercard Inc.
Q4 2014 $86.16 Open $538.02 +524.44% Open History
MCO - Moody's Corp.
Q1 2016 $96.56 Open $494.73 +412.36% Open History
AXP - American Express Co.
Q4 2016 $74.08 Open $355.06 +379.29% Open History
MU - Micron Technology, Inc.
Q3 2019 $42.85 Q3 2025 $167.32 +290.48% Closed History
GOOGL - Alphabet Inc.
Q2 2020 $70.88 Q3 2025 $243.13 +243.04% Closed History
BRK.A - Berkshire Hathaway CL A
Q4 2016 $244,133.33 Open $737,000.00 +201.88% Open History
BRK.B - Berkshire Hathaway CL B
Q4 2016 $162.98 Open $491.09 +201.32% Open History
BAC - Bank of America Corp.
Q4 2016 $22.10 Q3 2025 $51.59 +133.44% Closed History
DJCO - Daily Journal Corp.
Q2 2021 $338.52 Open $570.68 +68.58% Open History
STLA - Stellantis N.V.
Q4 2014 $7.64 Q3 2020 $12.27 +60.64% Closed History
0E41 - Enlink Midstream LLC
Q1 2016 $11.13 Q3 2017 $16.69 +49.96% Closed History
GM.WS.B - General Motors Co
Q4 2014 $10.93 Q4 2018 $15.69 +43.55% Closed History
TWTR - Twitter Inc
Q2 2020 $29.80 Q1 2022 $38.70 +29.87% Closed History
BAC.WS.A - Bank Amer Corp
Q4 2016 $9.95 Q4 2018 $12.84 +29.05% Closed History
C - Citigroup Inc.
Q4 2014 $54.11 Q2 2018 $66.92 +23.67% Closed History
PKX - Posco
Q4 2014 $63.81 Q2 2018 $74.16 +16.22% Closed History
CNR - Core Natural Resources, Inc.
Q1 2025 $77.09 Q3 2025 $83.52 +8.34% Closed History
AXP - American Express Co.
Q4 2014 $93.04 Q4 2014 $93.04 +0.00% Closed History
BAC - Bank of America Corp.
Q4 2014 $17.89 Q4 2014 $17.89 +0.00% Closed History
BAC.WS.A - Bank Of America Corp
Q4 2014 $7.00 Q4 2014 $7.00 +0.00% Closed History
BRK.A - Berkshire Hathaway CL A
Q4 2014 $226,000.00 Q4 2014 $226,000.00 +0.00% Closed History
BRK.B - Berkshire Hathaway CL B
Q4 2014 $150.15 Q4 2014 $150.15 +0.00% Closed History
DIG1 - Directv
Q4 2014 $86.70 Q4 2014 $86.70 +0.00% Closed History
GS - The Goldman Sachs Group, Inc.
Q4 2014 $193.82 Q4 2014 $193.82 +0.00% Closed History
TERP - Terraform Pwr Inc
Q2 2017 $12.00 Q4 2018 $11.22 -6.50% Closed History
ARCH - Arch Resources Inc
Q2 2024 $152.22 Q4 2024 $141.23 -7.22% Closed History
WFC.WS - Wells Fargo &  Co
Q4 2014 $21.30 Q3 2018 $19.27 -9.53% Closed History
BABA - Alibaba Group Holdings Ltd.
Q2 2021 $226.78 Q3 2025 $178.74 -21.18% Closed History
WFC - Wells Fargo & Co.
Q4 2014 $54.82 Q1 2021 $39.07 -28.73% Closed History
TOO - Teekay Offshore Partners L P
Q4 2017 $2.36 Q4 2019 $1.54 -34.75% Closed History
AMR - Alpha Metallurgical Resources, Inc.
Q2 2024 $280.50 Q3 2025 $164.13 -41.49% Closed History
ZINCQ - Horsehead Holding Corp
Q4 2014 $15.83 Q4 2015 $2.05 -87.05% Closed History
SRG - Seritage Growth Properties
Q1 2016 $49.97 Q3 2025 $4.25 -91.49% Closed History
CRESW - Cresud SA Comercial
Q4 2014 $0.01 Q1 2015 $0.02 data error Closed History
Entry/exit prices and returns are split-adjusted to today's share basis. The quarter-by-quarter history shows prices exactly as filed with the SEC, so a pre-split quarter's price will look higher than the split-adjusted entry above.