Q1 2026 · 13F-HR
ACK Asset Management LLCholdings as filed
Filed 2026-05-15 · accession 0001510940-26-000004
$801.1M
Reported value
20
Positions
2026-03-31
Period end
The Brief · ACK Asset Management LLC · Q1 2026
AI · grounded in 13F
ACK Asset Management LLC exited its position in ENS, reducing its exposure by $44.7M. The fund established three new positions, led by a $45.8M investment in LFUS, followed by entries into CTS at $27.9M and SWIM at $27.7M. Other notable exits included closing positions in ATRO for $32.4M and AIN for $30.4M.
Holdings as filed
| CUSIP | Ticker | Issuer | Value | % port. | Shares | Class | Voting |
|---|---|---|---|---|---|---|---|
| 576690101 | MTRN | MTRN | $68.7M | 8.57% | 474,800 | Common | SOLE |
| 00790R104 | WMS | WMS | $53.5M | 6.68% | 390,000 | Common | SOLE |
| 00217Y104 | ATS | ATS | $52.1M | 6.50% | 1,846,196 | Common | SOLE |
| 775133101 | ROG | ROG | $51.0M | 6.36% | 475,000 | Common | SOLE |
| 42328H109 | HLIO | HLIO | $50.5M | 6.30% | 780,378 | Common | SOLE |
| 537008104 | LFUS | LFUS | $45.8M | 5.72% | 135,000 | Common | SOLE |
| 21874C102 | CNM | CNM | $44.5M | 5.55% | 900,000 | Common | SOLE |
| 67000B104 | NOVT | NOVT | $44.3M | 5.53% | 375,000 | Common | SOLE |
| 82982L103 | SITE | SITE | $43.9M | 5.48% | 330,000 | Common | SOLE |
| 046224101 | ASTE | ASTE | $42.3M | 5.29% | 786,500 | Common | SOLE |
| G4253H101 | JHX | JHX | $39.8M | 4.96% | 2,100,000 | Common | SOLE |
| 233377407 | DXPE | DXPE | $36.3M | 4.53% | 260,000 | Common | SOLE |
| 14154A102 | CDNL | CDNL | $34.7M | 4.33% | 874,000 | Common | SOLE |
| 26969P108 | EXP | EXP | $31.3M | 3.90% | 165,000 | Common | SOLE |
| 57638P104 | MBC | MBC | $30.7M | 3.84% | 3,700,000 | Common | SOLE |
| 387328107 | GVA | GVA | $30.0M | 3.74% | 250,000 | Common | SOLE |
| 126501105 | CTS | CTS | $27.9M | 3.48% | 584,000 | Common | SOLE |
| 51819L107 | SWIM | SWIM | $27.7M | 3.46% | 5,160,000 | Common | SOLE |
| H55555108 | MTASF | AERO-SWX | $26.8M | 3.35% | 830,000 | Common | SOLE |
| 18482P103 | CLFD | CLFD | $19.5M | 2.43% | 735,200 | Common | SOLE |
Source: SEC EDGAR · raw 13F holdings as filed. The Class column shows the option type when reported (Put/Call) or Common when the issuer's equity is held directly. 13F discloses long positions only.