ACK Asset Management LLC
In its 13F for Q2 2025 (holdings as of June 30, 2025, filed August 13, 2025), ACK Asset Management LLC reported 21 stock positions worth $761.4 million. Its top holding was Astronics (ATRO) at 9.1% of the portfolio, followed by Ats (ATS, 7.7%) and Dycom Industries (DY, 7.2%). Compared with Q1 2025, it opened 6 new positions, sold out of 5, added to 5 and reduced 9. The biggest buy was a new position in Albany Intl Class A (AIN) and the biggest sale Mastec (MTZ, shares −73%).
- Most Recent 13F
- Q2 2026
- Location
- GREENWICH, CT
- CIK
- 0001510940
- Portfolio Value
- $761.4M (Q2 2025)
- SEC Filing
- 0001510940-25-000005 ↗ filed Aug 13, 2025
Holdings Value
Holdings 21 stocks · $761.4M
| ATRO Astronics Corp. | 9.06% | 2,060,000 | $69.0M | No change |
| ATS Ats Corp. | 7.73% | 1,846,196 | $58.9M | Reduce -8.3% |
| DY Dycom Industries Inc. | 7.21% | 224,700 | $54.9M | Reduce -41.3% |
| GVA Granite Construction Inc. | 6.69% | 545,000 | $51.0M | Add +185.8% |
| ENS Enersys | 6.58% | 584,324 | $50.1M | Reduce -6.4% |
| MYRG MYR Group Inc./Delaware | 6.32% | 265,200 | $48.1M | Reduce -5.0% |
| CTRI Centuri Holdings Inc. | 5.99% | 2,032,000 | $45.6M | Add +66.5% |
| JBTM JBT Marel Corp. | 5.54% | 350,546 | $42.2M | Reduce -5.2% |
| MTRN Materion Corp. | 5.47% | 524,800 | $41.7M | Add +14.3% |
| AIN Albany Intl Corp. Class A | 5.39% | 585,000 | $41.0M | New |
| RRX Regal Rexnord Corp. | 5.24% | 275,000 | $39.9M | New |
| WMS Advanced Drainage Systems Inc. | 5.20% | 345,000 | $39.6M | New |
| MRC MRC Global Inc. | 4.08% | 2,267,000 | $31.1M | Add +44.9% |
| SITE Siteone Landscape Supply Inc. | 3.97% | 250,000 | $30.2M | Add +150.0% |
| MIR Mirion Technologies Inc. | 3.78% | 1,337,000 | $28.8M | Reduce -17.4% |
| CLFD Clearfield Inc. | 3.56% | 625,200 | $27.1M | Reduce -9.0% |
| MTZ Mastec Inc. | 2.80% | 125,000 | $21.3M | Reduce -73.0% |
| MTRX Matrix Service Co. | 1.93% | 1,087,100 | $14.7M | Reduce -8.2% |
| NPKI NPK International Inc. | 1.37% | 1,226,808 | $10.4M | New |
| CTOS Custom Truck One Source Inc. | 1.22% | 1,875,000 | $9.3M | New |
| DXPE DXP Enterprises Inc. | 0.87% | 75,600 | $6.6M | New |
Portfolio Sells Q1 2025 → Q2 2025
| MTZ Mastec Inc. | Reduce -73.0% | 2.80% | −6.07 |
| ROG Rogers Corp. | Sold out | 0.00% | −5.74 |
| CECO Ceco Environmental Corp. | Sold out | 0.00% | −4.50 |
| ENS Enersys | Reduce -6.4% | 6.58% | −2.81 |
| MBC Masterbrand Inc. | Sold out | 0.00% | −2.79 |
| BIRDF Bird Construction Inc. | Sold out | 0.00% | −2.79 |
| DY Dycom Industries Inc. | Reduce -41.3% | 7.21% | −2.36 |
| JBTM JBT Marel Corp. | Reduce -5.2% | 5.54% | −1.88 |
| LASR Nlight Inc. | Sold out | 0.00% | −0.96 |
| ATS Ats Corp. | Reduce -8.3% | 7.73% | −0.51 |
| MTRX Matrix Service Co. | Reduce -8.2% | 1.93% | −0.49 |
| MIR Mirion Technologies Inc. | Reduce -17.4% | 3.78% | −0.07 |
| CLFD Clearfield Inc. | Reduce -9.0% | 3.56% | +0.21 |
| MYRG MYR Group Inc./Delaware | Reduce -5.0% | 6.32% | +1.14 |
Portfolio Buys Q1 2025 → Q2 2025
| AIN Albany Intl Corp. Class A | New | 5.39% | +5.39 |
| RRX Regal Rexnord Corp. | New | 5.24% | +5.24 |
| WMS Advanced Drainage Systems Inc. | New | 5.20% | +5.20 |
| GVA Granite Construction Inc. | Add +185.8% | 6.69% | +4.33 |
| CTRI Centuri Holdings Inc. | Add +66.5% | 5.99% | +2.70 |
| SITE Siteone Landscape Supply Inc. | Add +150.0% | 3.97% | +1.98 |
| NPKI NPK International Inc. | New | 1.37% | +1.37 |
| CTOS Custom Truck One Source Inc. | New | 1.22% | +1.22 |
| MRC MRC Global Inc. | Add +44.9% | 4.08% | +1.13 |
| DXPE DXP Enterprises Inc. | New | 0.87% | +0.87 |
| MTRN Materion Corp. | Add +14.3% | 5.47% | −0.68 |
All Filings
| Quarter | Positions | 13F Reported Value | Top Holdings |
|---|---|---|---|
| Q2 2026 | 21 | $856.3M | WMS, HLIO, LFUS, JHX, GTX |
| Q1 2026 | 20 | $801.1M | MTRN, WMS, ATS, ROG, HLIO |
| Q4 2025 | 23 | $796.8M | MTRN, GVA, WMS, ATS, CNM |
| Q3 2025 | 20 | $799.1M | ENS, MTRN, GVA, ATRO, WMS |
| Q2 2025 | 21 | $761.4M | ATRO, ATS, DY, GVA, ENS |
| Q1 2025 | 20 | $609.0M | DY, ENS, MTZ, ATS, ATRO |
| Q4 2024 | 22 | $746.4M | DY, MTZ, ATS, ENS, ROG |
| Q3 2024 | 18 | $809.2M | DY, MTZ, ENS, ROG, ATS |
| Q2 2024 | 19 | $810.3M | DY, MTZ, ENS, ROG, CNM |
| Q1 2024 | 20 | $858.3M | CNM, DY, ATKR, MTZ, ENS |