Stocks/Funds/CIK 1510940

ACK Asset Management LLC

long-term holderconcentrated
Quarterly 13F filings · Latest period 2026-03-31 · CIK 1510940
Assets
$801M
+31.6% YoY
Holdings
20
Lifetime alpha vs market
+4.36% annual
Average hold time
2.1 yr
median 1.4 yr

Quarterly history

Cum return +99% vs S&P +66% · α +33% lifetimeAUM $801M · peak $901MFlow $-55M (-7%)2016-062017-122019-062020-122022-062023-122025-062026-03
AUM ($B)fundS&P 500(gap = α)/ Flow in/out

Behavior signals (lifetime)

Dip response
+3.56%
adds when stocks drop
when a holding falls −10%+
Middle response
+1.51%
steady accumulation
Rally response
-7.97%
trims into rallies
when a holding rises +10%+

Top positions · 20

Ticker$ value% portYoYHold time
MTRNMaterion Corporation$69M8.6%+78.2%6.8 yr
WMSAdvanced Drainage System$53M6.7%+26.9%5.5 yr
$52M6.5%3.5 yr
ROGRogers Corporation$51M6.4%+58.9%7.5 yr
HLIOHelios Technologies, Inc$50M6.3%+103.5%2.5 yr
LFUSLittelfuse, Inc.$46M5.7%+74.5%0.3 yr
CNMCore & Main, Inc.$44M5.5%+2.3%2.3 yr
NOVTNovanta Inc.$44M5.5%-7.6%0.5 yr
SITESiteOne Landscape Supply$44M5.5%+9.6%1.3 yr
ASTEAstec Industries, Inc.$42M5.3%+58.1%0.8 yr
$40M5.0%0.8 yr
DXPEDXP Enterprises, Inc.$36M4.5%+69.9%0.8 yr
CDNLCardinal Infrastructure $35M4.3%0.5 yr
EXPEagle Materials Inc.$31M3.9%-14.2%2.3 yr
MBCMasterBrand, Inc.$31M3.8%-36.4%1.5 yr

Portfolio composition (YoY)

Industry mix
Hardware, Equipment & Parts21.1%+15.4pp$169M
Industrial - Distribution15.6%+13.6pp$125M
Unknown14.8%+6.6pp$119M
Construction10.1%$81M
Industrial Materials8.6%+2.4pp$69M
Industrial - Machinery6.3%-5.0pp$50M
Agricultural - Machinery5.3%$42M
Industrial - Infrastructure Operations4.3%$35M
Construction Materials3.9%$31M
Furnishings, Fixtures & Appliances3.8%+1.0pp$31M
Country
US85.2%-3.8pp
Unknown14.8%+6.6pp
Top 5: 34.4% · Top 10: 62.0% · Top 25: 100.0%

Winners

TickerPrev $PnLYoY %
MTRN$37M+0.03B78.2%
ROG$35M+0.02B58.9%
GVA$14M+0.01B59.6%
SITE$12M+0.00B9.6%
CLFD$20M-0.00B-10.9%

Losers

TickerPrev $PnLYoY %
MBC$17M-0.01B-36.4%
CLFD$20M-0.00B-10.9%

Top buys this quarter · 9

LFUS Littelfuse, Inc.new+$46M
CTS CTS Corporation+$20M
SWIM Latham Group, Inc.+$20M
MBC MasterBrand, Inc.+$12M
ROG Rogers Corporation+$4M
CLFD Clearfield, Inc.+$3M
DXPE DXP Enterprises, Inc.+$3M
CDNL Cardinal Infrastructure Group +$1M
+$0M

Top sells this quarter · 7

ENS EnerSysexit$53M
ATRO Astronics Corporationexit$40M
AIN Albany International Corp.exit$31M
GVA Granite Construction Incorpora$30M
APOG Apogee Enterprises, Inc.exit$27M
ERII Energy Recovery, Inc.exit$7M
CTOS Custom Truck One Source, Inc.exit$5M

Quarterly history (TTM returns)

PeriodAUM# PosReturn (1yr)SPY (1yr)Alpha (1yr)Flow
2026-03-31$801M20+56.15%+17.59%+38.56%-0.05B
2025-12-31$797M23+30.00%+17.72%+12.28%-0.03B
2025-09-30$799M20+26.30%+17.52%+8.78%-0.06B
2025-06-30$761M21+17.35%+14.94%+2.41%+0.00B
2025-03-31$609M20-7.66%+8.30%-15.96%-0.06B
2024-12-31$746M22+12.07%+24.89%-12.81%-0.07B
2024-09-30$809M18+19.11%+36.04%-16.92%-0.04B
2024-06-30$810M19+0.19%+24.49%-24.30%-0.03B
2024-03-31$858M20+18.04%+29.62%-11.59%-0.04B
2023-12-31$831M21+23.18%+26.18%-3.00%+0.09B
2023-09-30$688M21+34.73%+21.57%+13.16%-0.10B
2023-06-30$901M25+56.64%+19.42%+37.21%+0.14B
2023-03-31$655M23+11.80%-7.82%+19.62%+0.04B
2022-12-31$545M25+17.33%+7.56%+9.77%+0.10B
2022-09-30$378M23+2.02%-4.93%+6.95%+0.01B
2022-06-30$357M21-17.55%-16.11%-1.43%-0.02B