ACK Asset Management LLC
CIK 1510940 · View on SEC EDGAR ↗
- Portfolio value
- $856.3M
- Positions
- 21
- As of
- June 30, 2026
#2,717 of 9,443 by 13F value · top 28.8%
Portfolio value QoQ: +6.9% 13F does not disclose cash
- Top 10 holdings weight
- 60.24%
- Top 25 holdings weight
- 100.00%
- Positions above 1%
- 21
- Effective number of positions
- 19.1
Based on 13F long-equity holdings only (cash, bonds, shorts not disclosed)
Turnover Q2 2026: 30.9% Est. buys $256,044,554 · sells $354,450,486
Median holding: 3.0 quarters Tracked Q4 2024–Q2 2026 · 42.0% still held
- New positions
- 7
- Increased
- 5
- Decreased
- 5
- Closed
- 6
On this page
- Performance vs S&P How this manager's 13F portfolio performed against the S&P 500.
- Sector breakdown How the portfolio splits across market sectors.
- Portfolio Every stock this institution reports holding, from its latest 13F.
- Biggest new bets Brand-new positions opened in the latest quarter.
- Top moves The biggest position increases and decreases this quarter.
- Exited positions Positions the manager fully sold out of last quarter.
Performance vs S&P 500
Annualized: +53.7% · S&P 500: +18.0%
Approximates a buy-and-hold portfolio built from quarterly SEC 13F snapshots. Excludes cash, short positions, options/derivatives, and non-13(f) securities — reflects the disclosed long-equity book only, not total fund AUM. SEC filing lag is up to 45 days; this is not a real-time-copyable timing.
Priceable coverage: 97.7% · Options excluded: 0.0%
Sector breakdown
Industrials
70.5%
Consumer Discretionary
15.3%
Materials
4.7%
Communications
3.8%
Other/Unmapped
5.8%
Full portfolio 21 positions
| Type | Streak | 8Q trend | |||||
|---|---|---|---|---|---|---|---|
| WMS Advanced Drainage Systems, Inc. Common Stock | $61,214,400 | 7.15% | 390,000 | $7,733,700 | |||
| HLIO Helios Technologies, Inc. Common Stock | $60,779,250 | 7.10% | 681,000 | $10,280,990 | Down ×1 | ||
| LFUS Littelfuse, Inc. - Common Stock | $56,916,250 | 6.65% | 125,000 | $11,104,000 | Down ×1 | ||
| JHX James Hardie Industries plc. Ordinary Shares | $54,978,000 | 6.42% | 2,100,000 | $15,204,000 | |||
| GTX Garrett Motion Inc. - Common Stock | $54,345,000 | 6.35% | 1,500,000 | Up ×1 | |||
| CNM Core & Main, Inc. Class A Common Stock | $52,592,500 | 6.14% | 1,090,000 | $8,132,500 | Up ×1 | ||
| EXP Eagle Materials Inc Common Stock | $49,500,000 | 5.78% | 220,000 | $18,240,750 | Up ×1 | ||
| ATS ATS Corporation Common Shares | $43,170,000 | 5.04% | 1,500,000 | $-8,892,727 | Down ×1 | ||
| ASTE Astec Industries, Inc. - Common Stock | $42,237,988 | 4.93% | 690,276 | $-107,172 | Down ×1 | ||
| MTRN Materion Corporation | $40,147,650 | 4.69% | 135,000 | $-28,532,170 | Down ×1 | ||
| BWA BorgWarner Inc. Common Stock | $39,840,000 | 4.65% | 600,000 | ||||
| DNOW DNOW Inc. Common Stock | $38,910,000 | 4.54% | 3,000,000 | Up ×1 | |||
| MBC MasterBrand, Inc. Common Stock | $38,073,000 | 4.45% | 3,700,000 | $7,326,000 | |||
| SITE SiteOne Landscape Supply, Inc. Common Stock | $37,755,300 | 4.41% | 330,000 | $-6,171,000 | |||
| SWIM Latham Group, Inc. - Common Stock | $36,620,200 | 4.28% | 5,660,000 | $8,911,000 | Up ×1 | ||
| CLFD Clearfield, Inc. - Common Stock | $32,237,858 | 3.76% | 810,200 | $12,777,114 | Up ×2 | ||
| ST Sensata Technologies Holding plc Ordinary Shares | $28,644,000 | 3.34% | 600,000 | Up ×1 | |||
| Unknown issuer (CUSIP: H55555108) | $28,460,408 | 3.32% | 1,082,500 | $1,654,101 | Up ×2 | ||
| SHLS Shoals Technologies Group, Inc. - Class A Common Stock | $22,324,500 | 2.61% | 2,255,000 | Up ×1 | |||
| EQPT EquipmentShare.com Inc - Class A Common Stock | $20,934,558 | 2.44% | 1,064,830 | Up ×1 | |||
| MEI Methode Electronics, Inc. Common Stock | $16,646,175 | 1.94% | 877,500 | Up ×1 | |||
| No matches | |||||||
Biggest new bets
New positions opened this quarter, largest first.
Top movers (QoQ)
| Security | Action | Shares Δ | Value Δ |
|---|---|---|---|
| MTRN | Trimmed | -340K | -$28.5M |
| EXP | Bought more | +55K | +$18.2M |
| JHX | Price move only | +0 | +$15.2M |
| CLFD | Bought more | +75K | +$12.8M |
| LFUS | Trimmed | -10K | +$11.1M |
| HLIO | Trimmed | -99K | +$10.3M |
| SWIM | Bought more | +500K | +$8.9M |
| ATS | Trimmed | -346K | -$8.9M |
| CNM | Bought more | +190K | +$8.1M |
| WMS | Price move only | +0 | +$7.7M |
Exited positions
Includes corporate events (mergers, delistings) — not all exits are sells
Closed positions reflect 13F reporting changes; for index managers these are often mechanical (delisting, M&A, index rebalancing), not active decisions.
| Security | Quarter | Shares before | Value before | Price since exit |
|---|---|---|---|---|
| DY | Sept. 30, 2025 | 224,700 | $54,914,433 | 36.9% |
| ROG | June 30, 2026 | 475,000 | $50,981,750 | -21.2% |
| JBTM | Dec. 31, 2025 | 350,546 | $49,234,186 | -23.7% |
| MYRG | Sept. 30, 2025 | 265,200 | $48,120,540 | 54.9% |
| ENS | March 31, 2026 | 304,324 | $44,659,547 | 10.0% |
| NOVT | June 30, 2026 | 375,000 | $44,291,250 | -10.8% |
| RRX | Sept. 30, 2025 | 275,000 | $39,864,000 | 16.7% |
| DXPE | June 30, 2026 | 260,000 | $36,329,800 | 11.9% |
| ROG | June 30, 2025 | 517,500 | $34,946,775 | 88.4% |
| CDNL | June 30, 2026 | 874,000 | $34,658,470 | -55.4% |
| ATRO | March 31, 2026 | 597,469 | $32,406,719 | 19.6% |
| MRC | Sept. 30, 2025 | 2,267,000 | $31,080,570 | No longer tracked |
| AIN | March 31, 2026 | 600,000 | $30,420,000 | 14.3% |
| GVA | June 30, 2026 | 250,000 | $29,970,000 | -20.8% |
| APOG | March 31, 2026 | 813,000 | $29,601,330 | 22.3% |
| CTRI | Dec. 31, 2025 | 1,375,000 | $29,108,750 | -11.4% |
| MIR | Sept. 30, 2025 | 1,337,000 | $28,785,610 | -33.6% |
| CTS | June 30, 2026 | 584,000 | $27,891,840 | -11.3% |
| CECO | June 30, 2025 | 1,201,000 | $27,382,800 | 160.0% |
| MTZ | Sept. 30, 2025 | 125,000 | $21,303,750 | 26.8% |
| ESI | March 31, 2025 | 750,000 | $19,072,500 | 57.2% |
| NPKI | Dec. 31, 2025 | 1,576,808 | $17,833,698 | 16.4% |
| MBC | June 30, 2025 | 1,302,500 | $17,010,650 | -16.5% |
| BIRDF | June 30, 2025 | 1,120,800 | $16,961,985 | No longer tracked |
| MTRX | Sept. 30, 2025 | 1,087,100 | $14,686,721 | -13.4% |
| NEOG | March 31, 2025 | 1,206,796 | $14,650,503 | 39.1% |
| APTV | March 31, 2025 | 240,000 | $14,515,200 | -19.2% |
| BWA | March 31, 2025 | 351,400 | $11,171,006 | 129.6% |
| ERII | March 31, 2026 | 677,251 | $9,136,116 | -23.4% |
| DXPE | Sept. 30, 2025 | 75,600 | $6,626,340 | 58.6% |
| LASR | June 30, 2025 | 754,000 | $5,858,580 | 143.1% |
| TRNS | March 31, 2025 | 45,000 | $4,758,300 | 22.2% |
| CTOS | March 31, 2026 | 800,136 | $4,608,783 | 47.6% |