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Super Investors ACK Asset Management LLC
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ACK Asset Management LLC

Quarterly 13F snapshot: US-listed longs only, no performance figures — 13F data cannot support them.

Portfolio value
$856M
Positions
21
Quarter ended
June 30, 2026
Filed
August 13, 2026

Reported portfolio value by quarter (53 quarters reported)

$858M $195M
Q2 13 Q1 16 Q4 18 Q3 21 Q2 24 Q2 26

$247M in Q2 2013 → $856M now. Hover for any quarter.

Holdings

As reported for the quarter ended June 30, 2026. Activity is the change in share count since the prior quarter's filing.

Holding % of portfolio Activity Shares Value
W Wms 7.1% Unchanged 390,000 $61.2M
H Hlio 7.1% Trimmed 13% 681,000 $60.8M
L Lfus 6.6% Trimmed 7.4% 125,000 $56.9M
J Jhx 6.4% Unchanged 2,100,000 $55M
G Gtx 6.3% New 1,500,000 $54.3M
C Cnm 6.1% Added 21% 1,090,000 $52.6M
E Exp 5.8% Added 33% 220,000 $49.5M
Ats 5.0% Trimmed 19% 1,500,000 $43.2M
A Aste 4.9% Trimmed 12% 690,276 $42.2M
M Mtrn 4.7% Trimmed 72% 135,000 $40.1M
B Bwa 4.7% New 600,000 $39.8M
Dnow 4.5% New 3,000,000 $38.9M
M Mbc 4.4% Unchanged 3,700,000 $38.1M
S Site 4.4% Unchanged 330,000 $37.8M
S Swim 4.3% Added 9.7% 5,660,000 $36.6M
C Clfd 3.8% Added 10% 810,200 $32.2M
S St 3.3% New 600,000 $28.6M
A Aero-swx 3.3% Added 30% 1,082,500 $28.5M
S Shls 2.6% New 2,255,000 $22.3M
E Eqpt 2.4% New 1,064,830 $20.9M
M Mei 1.9% New 877,500 $16.6M

Timeline of changes

What changed each quarter, from the filings' own share counts. Largest moves first; most recent 8 quarters.

Q2 2026

quarter ended June 30, 2026 · filed August 13, 2026

Company Action Shares changed Value of change % of portfolio
M Mtrn Trimmed −339,800 −$101M 4.7%
G Gtx New +1,500,000 +$54.3M 6.3%
R Rog Exited −475,000 −$51M —
N Novt Exited −375,000 −$44.3M —
B Bwa New +600,000 +$39.8M 4.7%
Dnow New +3,000,000 +$38.9M 4.5%
D Dxpe Exited −260,000 −$36.3M —
C Cdnl Exited −874,000 −$34.7M —
G Gva Exited −250,000 −$30M —
S St New +600,000 +$28.6M 3.3%

Showing the 10 largest of 23 changes.

Q1 2026

quarter ended March 31, 2026 · filed May 15, 2026

Company Action Shares changed Value of change % of portfolio
L Lfus New +135,000 +$45.8M 5.7%
E Ens Exited −304,324 −$44.7M —
A Atro Exited −597,469 −$32.4M —
A Ain Exited −600,000 −$30.4M —
G Gva Trimmed −250,000 −$30M 3.7%
A Apog Exited −813,000 −$29.6M —
Cts New +584,000 +$27.9M 3.5%
S Swim New +5,160,000 +$27.7M 3.5%
A Aero-swx Added +675,149 +$21.8M 3.3%
M Mbc Added +1,400,000 +$11.6M 3.8%

Showing the 10 largest of 16 changes.

Q4 2025

quarter ended December 31, 2025 · filed February 13, 2026

Company Action Shares changed Value of change % of portfolio
J Jbtm Exited −350,546 −$49.2M —
N Novt New +375,000 +$44.6M 5.6%
E Ens Trimmed −280,000 −$41.1M 5.6%
R Rog New +436,707 +$40M 5.0%
A Atro Trimmed −632,531 −$34.3M 4.1%
C Ctri Exited −1,375,000 −$29.1M —
D Dxpe New +240,000 +$26.3M 3.3%
C Cdnl New +844,591 +$20.4M 2.6%
N Npki Exited −1,576,808 −$17.8M —
E Exp Added +75,000 +$15.5M 4.3%

Showing the 10 largest of 20 changes.

Q3 2025

quarter ended September 30, 2025 · filed November 14, 2025

Company Action Shares changed Value of change % of portfolio
D Dy Exited −224,700 −$54.9M —
C Cnm New +900,000 +$48.4M 6.1%
M Myrg Exited −265,200 −$48.1M —
J Jhx New +2,100,000 +$40.3M 5.0%
H Hlio New +770,000 +$40.1M 5.0%
R Rrx Exited −275,000 −$39.9M —
A Atro Trimmed −830,000 −$37.9M 7.0%
A Aste New +701,500 +$33.8M 4.2%
M Mrc Exited −2,267,000 −$31.1M —
A Apog New +708,000 +$30.8M 3.9%

Showing the 10 largest of 22 changes.

Q2 2025

quarter ended June 30, 2025 · filed August 13, 2025

Company Action Shares changed Value of change % of portfolio
M Mtz Trimmed −337,700 −$57.6M 2.8%
A Ain New +585,000 +$41M 5.4%
R Rrx New +275,000 +$39.9M 5.2%
W Wms New +345,000 +$39.6M 5.2%
D Dy Trimmed −158,100 −$38.6M 7.2%
Rogers Corp Exited −517,500 −$34.9M —
G Gva Added +354,300 +$33.1M 6.7%
Ceco Environmental Corp Exited −1,201,000 −$27.4M —
C Ctri Added +811,409 +$18.2M 6.0%
S Site Added +150,000 +$18.1M 4.0%

Showing the 10 largest of 25 changes.

Q1 2025

quarter ended March 31, 2025 · filed May 13, 2025

Company Action Shares changed Value of change % of portfolio
E Esi Exited −750,000 −$19.1M —
BC Bird Construction Inc New +1,120,800 +$17M 2.8%
N Neog Exited −1,206,796 −$14.7M —
A Aptv Exited −240,000 −$14.5M —
Siteone Landscape Supply Inc New +100,000 +$12.1M 2.0%
Mrc Global Inc Added +1,015,000 +$11.7M 3.0%
B Bwa Exited −351,400 −$11.2M —
Dycom Industries Inc Trimmed −62,700 −$9.55M 9.6%
Myr Group Inc Added +79,100 +$8.95M 5.2%
Mastec Inc Trimmed −69,100 −$8.06M 8.9%

Showing the 10 largest of 24 changes.

Q4 2024

quarter ended December 31, 2024 · filed February 13, 2025

Company Action Shares changed Value of change % of portfolio
J Jbt New +400,000 +$50.8M 6.8%
G Gva Trimmed −541,000 −$47.5M 3.3%
M Mir Trimmed −2,431,300 −$42.4M 4.2%
M Mtz Trimmed −240,500 −$32.7M 9.7%
E Esi Trimmed −1,240,000 −$31.5M 2.6%
M Myrg New +200,000 +$29.8M 4.0%
C Ctri New +1,300,000 +$25.1M 3.4%
P Prim Exited −390,000 −$22.7M —
D Dy Trimmed −90,000 −$15.7M 10.4%
A Aptv New +240,000 +$14.5M 1.9%

Showing the 10 largest of 24 changes.

Q3 2024

quarter ended September 30, 2024 · filed November 13, 2024

Company Action Shares changed Value of change % of portfolio
C Cnm Exited −1,352,000 −$66.2M —
A Arry Exited −4,282,000 −$43.9M —
P Prim New +390,000 +$22.7M 2.8%
E Esi Added +490,000 +$13.3M 6.7%
C Calx New +321,124 +$12.5M 1.5%
M Mbc New +650,000 +$12.1M 1.5%
M Mir Added +948,720 +$10.5M 5.8%
M Mtrx New +801,000 +$9.24M 1.1%
F Fip Exited −1,025,000 −$8.85M —
Ats Added +255,889 +$7.43M 8.1%

Showing the 10 largest of 14 changes.

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