ACK Asset Management LLC reported 20 positions worth $827.87M for the quarter ended Jun 30, 2026, up 6.9% on the prior quarter. It opened 7 new positions, added to 4, trimmed 5 and exited 6. Its largest holding is Advanced Drainage Systems, Inc. at 7.4% of the portfolio.
Reported 13F market value at each quarter end. A change mixes trading with price moves in the positions held.
Dollar value of shares bought and sold each quarter, at that quarter’s price. It counts trading only, not price changes.
How many positions were opened, added to, trimmed or closed each quarter.
Share of reported value in each sector at every quarter end.
| Holding | Change | Trade Value | Weight |
|---|---|---|---|
| GTX Garrett Motion Inc. | +1.50M | $54.34M | 6.56% |
| BWA Borgwarner Inc | +600.0K | $39.84M | 4.81% |
| DNOW DNOW Inc. | +3.00M | $38.91M | 4.7% |
| ST Sensata Technologies Holding plc | +600.0K | $28.64M | 3.46% |
| SHLS Shoals Technologies Group, Inc. | +2.26M | $22.32M | 2.7% |
| EQPT EquipmentShare.com Inc | +1.06M | $20.93M | 2.53% |
| MEI Methode Electronics Inc | +877.5K | $16.65M | 2.01% |
| EXP Eagle Materials Inc | +55.0K +33.3% | $12.38M | 5.98% |
| CNM Core & Main, Inc. | +190.0K +21.1% | $9.17M | 6.35% |
| SWIM Latham Group, Inc. | +500.0K +9.7% | $3.24M | 4.42% |
| Holding | Change | Trade Value | Weight |
|---|---|---|---|
| MTRN MATERION Corp | -339.8K -71.6% | $101.05M | 4.85% |
| ROG Rogers Corp | -475.0K -100.0% | $50.98M | Exited |
| NOVT Novanta Inc | -375.0K -100.0% | $44.29M | Exited |
| DXPE Dxp Enterprises Inc | -260.0K -100.0% | $36.33M | Exited |
| CDNL Cardinal Infrastructure Group Inc. | -874.0K -100.0% | $34.66M | Exited |
| GVA Granite Construction Inc | -250.0K -100.0% | $29.97M | Exited |
| CTS Cts Corp | -584.0K -100.0% | $27.89M | Exited |
| ATS ATS Corp | -346.2K -18.8% | $9.96M | 5.21% |
| HLIO Helios Technologies, Inc. | -99.4K -12.7% | $8.87M | 7.34% |
| ASTE Astec Industries Inc | -96.2K -12.2% | $5.89M | 5.1% |
| Holding | Shares | Trade Value | Weight |
|---|---|---|---|
| GTX Garrett Motion Inc. | +1.50M | $54.34M | 6.56% |
| BWA Borgwarner Inc | +600.0K | $39.84M | 4.81% |
| DNOW DNOW Inc. | +3.00M | $38.91M | 4.7% |
| ST Sensata Technologies Holding plc | +600.0K | $28.64M | 3.46% |
| SHLS Shoals Technologies Group, Inc. | +2.26M | $22.32M | 2.7% |
| EQPT EquipmentShare.com Inc | +1.06M | $20.93M | 2.53% |
| MEI Methode Electronics Inc | +877.5K | $16.65M | 2.01% |
| Holding | Shares Sold | Trade Value | Prior Weight |
|---|---|---|---|
| ROG Rogers Corp | -475.0K | $50.98M | 6.58% |
| NOVT Novanta Inc | -375.0K | $44.29M | 5.72% |
| DXPE Dxp Enterprises Inc | -260.0K | $36.33M | 4.69% |
| CDNL Cardinal Infrastructure Group Inc. | -874.0K | $34.66M | 4.48% |
| GVA Granite Construction Inc | -250.0K | $29.97M | 3.87% |
| CTS Cts Corp | -584.0K | $27.89M | 3.6% |
| # | Activity | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| 1 | WMS Advanced Drainage Systems, Inc. | Industrials | 390.0K | $61.21M | 7.39% | 0 | 0.0% | Unchanged | 0.51% |
| 2 | HLIO Helios Technologies, Inc. | Industrials | 681.0K | $60.78M | 7.34% | -99.4K | -12.7% | Reduced | 2.06% |
| 3 | LFUS Littelfuse Inc | Technology | 125.0K | $56.92M | 6.88% | -10.0K | -7.4% | Reduced | 0.49% |
| 4 | JHX James Hardie Industries plc | Industrials | 2.10M | $54.98M | 6.64% | 0 | 0.0% | Unchanged | 0.36% |
| 5 | GTX Garrett Motion Inc. | Industrials | 1.50M | $54.35M | 6.56% | +1.50M | – | New | 0.8% |
| 6 | CNM Core & Main, Inc. | Industrials | 1.09M | $52.59M | 6.35% | +190.0K | +21.1% | Added | 0.56% |
| 7 | EXP Eagle Materials Inc | Basic Materials | 220.0K | $49.50M | 5.98% | +55.0K | +33.3% | Added | 0.71% |
| 8 | ATS ATS Corp | Industrials | 1.50M | $43.17M | 5.21% | -346.2K | -18.8% | Reduced | 1.53% |
| 9 | ASTE Astec Industries Inc | Industrials | 690.3K | $42.24M | 5.1% | -96.2K | -12.2% | Reduced | 3% |
| 10 | MTRN MATERION Corp | Basic Materials | 135.0K | $40.15M | 4.85% | -339.8K | -71.6% | Reduced | 0.65% |
| 11 | BWA Borgwarner Inc | Industrials | 600.0K | $39.84M | 4.81% | +600.0K | – | New | 0.29% |
| 12 | DNOW DNOW Inc. | Industrials | 3.00M | $38.91M | 4.7% | +3.00M | – | New | 1.64% |
| 13 | MBC MasterBrand, Inc. | Consumer Discretionary | 3.70M | $38.07M | 4.6% | 0 | 0.0% | Unchanged | 1.82% |
| 14 | SITE SiteOne Landscape Supply, Inc. | Industrials | 330.0K | $37.76M | 4.56% | 0 | 0.0% | Unchanged | 0.75% |
| 15 | SWIM Latham Group, Inc. | Industrials | 5.66M | $36.62M | 4.42% | +500.0K | +9.7% | Added | 4.82% |
Tip. Select a row to see that position’s full history at ACK Asset Management.
As of its Q2 2026 13F filing, ACK Asset Management LLC’s five largest positions were Advanced Drainage Systems, Inc. (WMS) at 7.4%, Helios Technologies, Inc. (HLIO) at 7.3%, Littelfuse Inc (LFUS) at 6.9%, James Hardie Industries plc (JHX) at 6.6%, Garrett Motion Inc. (GTX) at 6.6% of the reported portfolio.
ACK Asset Management LLC reported a 13F portfolio worth $827.87M across 20 positions for Q2 2026. That is up 6.9% from the previous quarter.
Its largest purchases by value were Garrett Motion Inc. ($54.34M), Borgwarner Inc ($39.84M), DNOW Inc. ($38.91M). It opened 7 new positions.
Its largest sales by value were MATERION Corp ($101.05M), Rogers Corp ($50.98M), Novanta Inc ($44.29M). It exited 6 positions entirely.
From the Form 13F-HR reports ACK Asset Management LLC files with the SEC each quarter, within 45 days of quarter end. A 13F lists long positions in US-listed equities and options; it excludes short positions, cash, bonds and most non-US holdings.
13F data reflects long positions in US-listed equities and options as reported to the SEC up to 45 days after quarter end. It excludes short positions, cash, bonds and most non-US securities, so it is not a complete picture of a manager’s assets.