ACK Asset Management LLC
In its 13F for Q4 2025 (holdings as of December 31, 2025, filed February 13, 2026), ACK Asset Management LLC reported 23 stock positions worth $796.8 million. Its top holding was Materion (MTRN) at 7.4% of the portfolio, followed by Granite Construction (GVA, 7.2%) and Advanced Drainage Systems (WMS, 7.1%). Compared with Q3 2025, it opened 6 new positions, sold out of 3, added to 5 and reduced 6. The biggest buy was a new position in Novanta (NOVT) and the biggest sale an exit from JBT Marel (JBTM).
- Most Recent 13F
- Q2 2026
- Location
- GREENWICH, CT
- CIK
- 0001510940
- Portfolio Value
- $796.8M (Q4 2025)
- SEC Filing
- 0001510940-26-000001 ↗ filed Feb 13, 2026
Holdings Value
Holdings 23 stocks · $796.8M
| MTRN Materion Corp. | 7.41% | 474,800 | $59.0M | Reduce -9.5% |
| GVA Granite Construction Inc. | 7.24% | 500,000 | $57.7M | Reduce -8.3% |
| WMS Advanced Drainage Systems Inc. | 7.09% | 390,000 | $56.5M | No change |
| ATS Ats Corp. | 6.38% | 1,846,196 | $50.8M | No change |
| CNM Core & Main Inc. Class A | 5.87% | 900,000 | $46.8M | No change |
| ENS Enersys | 5.61% | 304,324 | $44.7M | Reduce -47.9% |
| NOVT Novanta Inc. | 5.60% | 375,000 | $44.6M | New |
| JHX James Hardie Ind PLC | 5.47% | 2,100,000 | $43.6M | No change |
| HLIO Helios Technologies Inc. | 5.24% | 780,378 | $41.7M | Add +1.4% |
| SITE Siteone Landscape Supply Inc. | 5.16% | 330,000 | $41.1M | Add +17.9% |
| ROG Rogers Corp. | 5.02% | 436,707 | $40.0M | New |
| EXP Eagle Materials Inc. | 4.28% | 165,000 | $34.1M | Add +83.3% |
| ASTE Astec Industries Inc. | 4.28% | 786,500 | $34.1M | Add +12.1% |
| ATRO Astronics Corp. | 4.07% | 597,469 | $32.4M | Reduce -51.4% |
| AIN Albany Intl Corp. Class A | 3.82% | 600,000 | $30.4M | Reduce -21.1% |
| APOG Apogee Enterprises Inc. | 3.72% | 813,000 | $29.6M | Add +14.8% |
| DXPE DXP Enterprises Inc. | 3.31% | 240,000 | $26.3M | New |
| MBC Masterbrand Inc. | 3.19% | 2,300,000 | $25.4M | No change |
| CDNL Cardinal Infrastructure GR-A | 2.56% | 844,591 | $20.4M | New |
| CLFD Clearfield Inc. | 2.29% | 625,200 | $18.2M | No change |
| ERII Energy Recovery Inc. | 1.15% | 677,251 | $9.1M | New |
| MTASF Montana Aerospace AG filed as AERO-SWX | 0.69% | 154,851 | $5.5M | New |
| CTOS Custom Truck One Source Inc. | 0.58% | 800,136 | $4.6M | Reduce -58.4% |
Portfolio Sells Q3 2025 → Q4 2025
| JBTM JBT Marel Corp. | Sold out | 0.00% | −6.16 |
| CTRI Centuri Holdings Inc. | Sold out | 0.00% | −3.64 |
| ATRO Astronics Corp. | Reduce -51.4% | 4.07% | −2.95 |
| ENS Enersys | Reduce -47.9% | 5.61% | −2.65 |
| NPKI NPK International Inc. | Sold out | 0.00% | −2.23 |
| AIN Albany Intl Corp. Class A | Reduce -21.1% | 3.82% | −1.25 |
| CTOS Custom Truck One Source Inc. | Reduce -58.4% | 0.58% | −0.97 |
| MTRN Materion Corp. | Reduce -9.5% | 7.41% | −0.53 |
| GVA Granite Construction Inc. | Reduce -8.3% | 7.24% | −0.24 |
Portfolio Buys Q3 2025 → Q4 2025
| NOVT Novanta Inc. | New | 5.60% | +5.60 |
| ROG Rogers Corp. | New | 5.02% | +5.02 |
| DXPE DXP Enterprises Inc. | New | 3.31% | +3.31 |
| CDNL Cardinal Infrastructure GR-A | New | 2.56% | +2.56 |
| EXP Eagle Materials Inc. | Add +83.3% | 4.28% | +1.66 |
| ERII Energy Recovery Inc. | New | 1.15% | +1.15 |
| MTASF Montana Aerospace AG | New | 0.69% | +0.69 |
| SITE Siteone Landscape Supply Inc. | Add +17.9% | 5.16% | +0.65 |
| HLIO Helios Technologies Inc. | Add +1.4% | 5.24% | +0.22 |
| ASTE Astec Industries Inc. | Add +12.1% | 4.28% | +0.05 |
| APOG Apogee Enterprises Inc. | Add +14.8% | 3.72% | −0.14 |
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 |