# ACK Asset Management LLC: Form 13F holdings

An institutional investment manager in GREENWICH, CT. SEC CIK 1510940.

- Quarter ended: 2026-06-30
- Filed: 2026-08-13
- Reported value: $856.3m
- Positions: 21 (21 lines in the filing's table; lines for the same security and option type are added together here)
- Compared with: the 13F for the quarter ended 2026-03-31
- Filing: https://www.sec.gov/Archives/edgar/data/1510940/000151094026000005/

## Holdings

As filed, largest first. Reported value is what the manager stated at the quarter end (Jun 30, 2026), in US dollars; it is filing data, not a price. Weight is the share of the total reported value.

| Issuer | Class | Reported value | Weight | Shares | Put or call | Change on the quarter before |
| --- | --- | ---: | ---: | ---: | --- | --- |
| [WMS (WMS)](/companies/wms.md) | COM | $61.2m | 7.1% | 390,000 |  | Unchanged |
| [HLIO (HLIO)](/companies/hlio.md) | COM | $60.8m | 7.1% | 681,000 |  | Reduced −99,378 |
| [LFUS (LFUS)](/companies/lfus.md) | COM | $56.9m | 6.6% | 125,000 |  | Reduced −10,000 |
| JHX | COM | $55.0m | 6.4% | 2,100,000 |  | Unchanged |
| [GTX (GTX)](/companies/gtx.md) | COM | $54.3m | 6.3% | 1,500,000 |  | New +1,500,000 |
| [CNM (CNM)](/companies/cnm.md) | COM | $52.6m | 6.1% | 1,090,000 |  | Added +190,000 |
| [EXP (EXP)](/companies/exp.md) | COM | $49.5m | 5.8% | 220,000 |  | Added +55,000 |
| [ATS (ATS)](/companies/ats.md) | COM | $43.2m | 5.0% | 1,500,000 |  | Reduced −346,196 |
| [ASTE (ASTE)](/companies/aste.md) | COM | $42.2m | 4.9% | 690,276 |  | Reduced −96,224 |
| [MTRN (MTRN)](/companies/mtrn.md) | COM | $40.1m | 4.7% | 135,000 |  | Reduced −339,800 |
| [BWA (BWA)](/companies/bwa.md) | COM | $39.8m | 4.7% | 600,000 |  | New +600,000 |
| [DNOW (DNOW)](/companies/dnow.md) | COM | $38.9m | 4.5% | 3,000,000 |  | New +3,000,000 |
| [MBC (MBC)](/companies/mbc.md) | COM | $38.1m | 4.4% | 3,700,000 |  | Unchanged |
| [SITE (SITE)](/companies/site.md) | COM | $37.8m | 4.4% | 330,000 |  | Unchanged |
| [SWIM (SWIM)](/companies/swim.md) | COM | $36.6m | 4.3% | 5,660,000 |  | Added +500,000 |
| [CLFD (CLFD)](/companies/clfd.md) | COM | $32.2m | 3.8% | 810,200 |  | Added +75,000 |
| ST | COM | $28.6m | 3.3% | 600,000 |  | New +600,000 |
| AERO-SWX | COM | $28.5m | 3.3% | 1,082,500 |  | Added +252,500 |
| [SHLS (SHLS)](/companies/shls.md) | COM | $22.3m | 2.6% | 2,255,000 |  | New +2,255,000 |
| [EQPT (EQPT)](/companies/eqpt.md) | COM | $20.9m | 2.4% | 1,064,830 |  | New +1,064,830 |
| [MEI (MEI)](/companies/mei.md) | COM | $16.6m | 1.9% | 877,500 |  | New +877,500 |

## Sold out

Held at the end of the quarter before and not reported this quarter.

| Issuer | Class | Reported value | Weight | Shares | Put or call | Change on the quarter before |
| --- | --- | ---: | ---: | ---: | --- | --- |
| [CDNL (CDNL)](/companies/cdnl.md) | COM | $0 | 0.0% | 0 |  | Sold out −874,000 |
| [CTS (CTS)](/companies/cts.md) | COM | $0 | 0.0% | 0 |  | Sold out −584,000 |
| [DXPE (DXPE)](/companies/dxpe.md) | COM | $0 | 0.0% | 0 |  | Sold out −260,000 |
| [GVA (GVA)](/companies/gva.md) | COM | $0 | 0.0% | 0 |  | Sold out −250,000 |
| [NOVT (NOVT)](/companies/novt.md) | COM | $0 | 0.0% | 0 |  | Sold out −375,000 |
| [ROG (ROG)](/companies/rog.md) | COM | $0 | 0.0% | 0 |  | Sold out −475,000 |

Source: SEC EDGAR, Form 13F-HR, accession 0001510940-26-000005. Last ingested by Listed: Oct 22, 2026, 05:26 ET. No prices; not investment advice.