Q2 2026 13F · SEC CIK 1510940
ACK Asset Management LLC
Hedge fundFiled 2026-08-13 for Q2 2026. Open the filing ↗ · All SEC filings ↗
- Reported 13F value
- $856.3M
- Reported positions
- 21
- Top holdings a year, 3 yrs
- +19.8%
- Assets under management
- $1.1B
ACK Asset Management LLC is a hedge fund that reported 21 positions worth $856.3M in its Q2 2026 13F, filed 2026-08-13. Its largest holdings were Advanced Drain Sys Inc Del (WMS, 7.1%), Helios Technologies Inc (HLIO, 7.1%), Littelfuse Inc (LFUS, 6.6%). A portfolio copying its top holdings returned 19.8% a year over the last 3 years, against 20.4% for the S&P 500.
ACK Asset Management LLC holdings all 21 positions.
Weights are shares of the filer's total reported 13F value, compared with Q1 2026. Share changes may reflect splits; weight changes also reflect price moves. A 13F shows long US-listed positions only, up to 135 days after the fact.
| Stock | % of 13F value | Share change | Reported value |
|---|---|---|---|
| WMSAdvanced Drain Sys Inc Del | 7.1% | +0.0% | $61.2M |
| HLIOHelios Technologies Inc | 7.1% | -12.7% | $60.8M |
| LFUSLittelfuse Inc | 6.6% | -7.4% | $56.9M |
| JHXJames Hardie Inds PLC | 6.4% | +0.0% | $55.0M |
| GTXGarrett Motion Inc | 6.3% | — | $54.3M |
| CNMCore & Main Inc | 6.1% | +21.1% | $52.6M |
| EXPEagle Matls Inc | 5.8% | +33.3% | $49.5M |
| ATSAts Corporation | 5.0% | -18.8% | $43.2M |
| ASTEAstec Inds Inc | 4.9% | -12.2% | $42.2M |
| MTRNMaterion Corp | 4.7% | -71.6% | $40.1M |
| BWABorgwarner Inc | 4.7% | — | $39.8M |
| DNOWDnow Inc (DNOW) | 4.5% | — | $38.9M |
| MBCMasterbrand Inc Common Stock | 4.4% | +0.0% | $38.1M |
| SITESiteone Landscape Supply Inc | 4.4% | +0.0% | $37.8M |
| SWIMLatham Group Inc | 4.3% | +9.7% | $36.6M |
| CLFDClearfield Incorporated | 3.8% | +10.2% | $32.2M |
| STSensata Technologies Hldg Pl | 3.3% | — | $28.6M |
| MTASFAero-Swx | 3.3% | +30.4% | $28.5M |
| SHLSShoals Technologies Group Cl A Ord | 2.6% | — | $22.3M |
| EQPTEquipmentshare Com Inc | 2.4% | — | $20.9M |
| MEIMethode Electrs Inc | 1.9% | — | $16.6M |
What ACK Asset Management LLC bought and sold in Q2 2026, against Q1 2026.
New positions
- GTX Garrett Motion Inc6.3% of 13F
- BWA Borgwarner Inc4.7% of 13F
- DNOW Dnow Inc (DNOW)4.5% of 13F
- ST Sensata Technologies Hldg Pl3.3% of 13F
- SHLS Shoals Technologies Group Cl A Ord2.6% of 13F
- EQPT Equipmentshare Com Inc2.4% of 13F
- MEI Methode Electrs Inc1.9% of 13F
Added to
- EXP Eagle Matls Inc+33.3% shares
- MTASF Aero-Swx+30.4% shares
- CNM Core & Main Inc+21.1% shares
- CLFD Clearfield Incorporated+10.2% shares
- SWIM Latham Group Inc+9.7% shares
Reduced
- MTRN Materion Corp-71.6% shares
- ATS Ats Corporation-18.8% shares
- HLIO Helios Technologies Inc-12.7% shares
- ASTE Astec Inds Inc-12.2% shares
- LFUS Littelfuse Inc-7.4% shares
Sold out
- ROG Rogers Corpwas 6.4%
- NOVT Novanta Incwas 5.5%
- DXPE Dxp Enterprises Incwas 4.5%
- CDNL Cardinal Infrastructure Groupwas 4.3%
- GVA Granite Constr Incwas 3.7%
- CTS Cts Corpwas 3.5%
Share counts compared with the Q1 2026 13F; a split also changes share counts.
How the holdings did against the S&P 500.
- 1 year
- +54.5% /yr
- S&P 500 +20.1%
- 3 years
- +19.8% /yr
- S&P 500 +20.4%
- 5 years
- +11.4% /yr
- S&P 500 +11.6%
A portfolio of the filer's 20 largest 13F positions, weighted by value, bought the trading day after each 13F was filed and held until the next one was: what copying this filer could have earned. 13Fs show long US-listed positions only, so this is an estimate of the stock picks, not the fund's reported returns.
Reported 13F value by quarter.
| Quarter | 13F value | Positions |
|---|---|---|
| Q2 2026 | $856.3M | 21 |
| Q1 2026 | $801.1M | 20 |
| Q4 2025 | $796.8M | 23 |
| Q3 2025 | $799.1M | 20 |
| Q2 2025 | $761.4M | 21 |
| Q1 2025 | $609.0M | 20 |
| Q4 2024 | $746.4M | 22 |
| Q3 2024 | $809.2M | 18 |
| Q2 2024 | $810.3M | 19 |
| Q1 2024 | $858.3M | 20 |
| Q4 2023 | $831.3M | 21 |
| Q3 2023 | $688.2M | 21 |
Questions about ACK Asset Management LLC's portfolio
What stocks does ACK Asset Management LLC own?
ACK Asset Management LLC's latest 13F, for Q2 2026 and filed Aug 13, 2026, lists 21 positions worth $856.3M. The largest are Advanced Drain Sys Inc Del (WMS) at 7.1%, Helios Technologies Inc (HLIO) at 7.1%, Littelfuse Inc (LFUS) at 6.6%, James Hardie Inds PLC (JHX) at 6.4% and Garrett Motion Inc (GTX) at 6.3%.
What did ACK Asset Management LLC buy last quarter?
In Q2 2026, ACK Asset Management LLC added a new position in Garrett Motion Inc (GTX), a new position in Borgwarner Inc (BWA), a new position in Dnow Inc (DNOW) (DNOW), a new position in Sensata Technologies Hldg Pl (ST), a new position in Shoals Technologies Group Cl A Ord (SHLS), Eagle Matls Inc (EXP) (+33.3% shares), Aero-Swx (MTASF) (+30.4% shares) and Core & Main Inc (CNM) (+21.1% shares), compared with its Q1 2026 filing.
What did ACK Asset Management LLC sell last quarter?
In Q2 2026, ACK Asset Management LLC sold all of Rogers Corp (ROG), sold all of Novanta Inc (NOVT), sold all of Dxp Enterprises Inc (DXPE), sold all of Cardinal Infrastructure Group (CDNL), sold all of Granite Constr Inc (GVA), Materion Corp (MTRN) (-71.6% shares), Ats Corporation (ATS) (-18.8% shares) and Helios Technologies Inc (HLIO) (-12.7% shares), compared with its Q1 2026 filing.
How has ACK Asset Management LLC's portfolio performed?
A portfolio copying ACK Asset Management LLC's 20 largest 13F holdings each quarter, from the day each filing was public, returned +19.8% a year over the last 3 years, against +20.4% for the S&P 500. Over 1 year: +54.5% against +20.1%. Over 5 years: +11.4% a year against +11.6%.
When is ACK Asset Management LLC's next 13F filing due?
13F filings are due 45 days after each quarter ends. ACK Asset Management LLC's filing for the quarter ending Sep 30, 2026 is due by Nov 14, 2026; this page updates the day after it is published.
How much money does ACK Asset Management LLC manage?
ACK Asset Management LLC reported $1.1B of regulatory assets under management on its latest SEC Form ADV. Its 13F, which covers only US-listed stocks and options, totals $856.3M.