Stocks/Funds/CIK 1381055

Penbrook Management LLC

long-term holder
Quarterly 13F filings · Latest period 2026-03-31 · CIK 1381055
Assets
$132M
-0.2% YoY
Holdings
93
Lifetime alpha vs market
-4.26% annual
Average hold time
5.4 yr
median 5.3 yr

Quarterly history

Cum return +113% vs S&P +218% · α -106% lifetimeAUM $132M · peak $166MFlow $-9M (-6%)2015-122018-062019-122021-062022-122024-062025-122026-03
AUM ($B)fundS&P 500(gap = α)/ Flow in/out

Behavior signals (lifetime)

Dip response
-3.19%
trims when stocks drop
when a holding falls −10%+
Middle response
-2.62%
baseline attrition
Rally response
-2.24%
trims into rallies
when a holding rises +10%+

Top positions · 30

Ticker$ value% portYoYHold time
NVONovo Nordisk A/S$12M8.8%-46.7%9.5 yr
AMZNAmazon.com, Inc.$11M8.2%+9.5%9.5 yr
MSFTMicrosoft Corporation$8M6.2%-0.6%9.5 yr
GOOGLAlphabet Inc.$7M5.0%9.5 yr
GOOGAlphabet Inc.$6M4.9%+84.3%9.5 yr
MCOMoody's Corporation$6M4.5%-5.6%9.5 yr
PLABPhotronics, Inc.$4M3.0%+94.7%8.5 yr
PLPlanet Labs PBC$3M2.2%+726.9%3.0 yr
AEHRAehr Test Systems$3M2.2%+408.6%2.3 yr
SASeabridge Gold Inc.$3M2.1%+142.8%9.5 yr
VETVermilion Energy Inc.$3M2.1%+77.8%8.5 yr
PRTAProthena Corporation plc$3M2.0%-21.5%0.3 yr
VMDViemed Healthcare, Inc.$3M1.9%+26.5%3.3 yr
$2M1.7%1.5 yr
$2M1.7%3.0 yr

Portfolio composition (YoY)

Industry mix
Biotechnology11.4%-5.4pp$15M
Internet Content & Information10.7%+4.3pp$14M
Semiconductors8.2%+4.0pp$11M
Specialty Retail8.2%+0.7pp$11M
Software - Infrastructure6.7%-0.9pp$9M
Oil & Gas Midstream6.1%-0.7pp$8M
Asset Management5.7%-1.1pp$8M
Financial - Data & Stock Exchanges4.5%-0.3pp$6M
Unknown4.4%-2.3pp$6M
Software - Application3.2%+1.0pp$4M
Country
US77.2%+6.4pp
DK8.8%-7.5pp
CA4.8%+2.5pp
Unknown4.4%-2.3pp
IE2.0%
JP1.1%-0.2pp
GB0.7%-0.4pp
CH0.6%+0.2pp
Top 5: 33.1% · Top 10: 47.1% · Top 25: 69.4%

Winners

TickerPrev $PnLYoY %
PL$1M+0.01B726.9%
GOOG$4M+0.00B84.3%
PLAB$2M+0.00B94.7%
SA$1M+0.00B142.8%
AEHR$0M+0.00B408.6%

Losers

TickerPrev $PnLYoY %
NVO$22M-0.01B-46.7%
ADP$2M-0.00B-31.8%
ALKT$1M-0.00B-40.3%
MCO$6M-0.00B-5.6%
SONY$2M-0.00B-18.3%

Top buys this quarter · 15

PRTA Prothena Corporation plcnew+$3M
EXTR Extreme Networks, Inc.new+$1M
CYRX Cryoport, Inc.+$1M
CURI CuriosityStream Inc.+$1M
MGNI Magnite, Inc.+$1M
BX Blackstone Inc.+$2M
PAR PAR Technology Corporation+$0M
PAYS PaySign, Inc.+$0M
DX Dynex Capital, Inc.new+$0M
PROF Profound Medical Corp.new+$0M

Top sells this quarter · 15

PL Planet Labs PBC$5M
AEHR Aehr Test Systems$2M
COHU Cohu, Inc.exit$1M
SYF Synchrony Financialexit$1M
BPOP Popular, Inc.$1M
PLAB Photronics, Inc.$4M
FNF Fidelity National Financial, I$1M
FBP First BanCorp.$0M
ACLS Axcelis Technologies, Inc.$0M
GPN Global Payments Inc.exit$0M

Quarterly history (TTM returns)

PeriodAUM# PosReturn (1yr)SPY (1yr)Alpha (1yr)Flow
2026-03-31$132M93+14.61%+17.59%-2.98%-0.01B
2025-12-31$145M97+6.86%+17.72%-10.85%-0.00B
2025-09-30$143M104-0.15%+17.52%-17.67%-0.00B
2025-06-30$140M111-8.60%+14.94%-23.54%-0.01B
2025-03-31$132M107-13.44%+8.30%-21.74%-0.00B
2024-12-31$147M110+6.48%+24.89%-18.41%+0.00B
2024-09-30$154M104+24.26%+36.04%-11.78%-0.00B
2024-06-30$164M101+23.73%+24.49%-0.76%-0.00B
2024-03-31$161M102+22.37%+29.62%-7.26%-0.00B
2023-12-31$149M102+13.31%+26.18%-12.87%-0.00B
2023-09-30$136M99-5.62%+21.57%-27.19%+0.00B
2023-06-30$138M98-12.46%+19.42%-31.89%+0.01B
2023-03-31$127M94-29.28%-7.82%-21.46%+0.01B
2022-12-31$117M95-34.65%-18.17%-16.48%+0.01B
2022-09-30$116M99-21.26%-15.51%-5.75%+0.00B
2022-06-30$127M106-11.32%-10.62%-0.70%-0.00B