ACK Asset Management LLC
13F filer · CIK 1510940 · Greenwich, CT
Summary
ACK Asset Management LLC reported $856.33M across 21 positions in its 13F for 2026 Q2, filed Aug 13, 2026. The largest holdings are WMS (7.1%), HLIO (7.1%), LFUS (6.6%). Versus 2026 Q1, leaving options aside, it opened 7 new positions, added to 5, trimmed 5 and sold out of 6.
Reported value$856.33M
Positions21
Report period2026 Q2
FiledAug 13, 2026
New positions7
Added5
Trimmed5
Sold out6
Top 21 holdings
By reported value, options listed separately · change vs 2026 Q1
Weight 7.1%Value $61.21MPrice $130.78Shares 390KSince Jun 30 -16.68%
Weight 7.1%Value $60.78MPrice $68.91Shares 681K -12.73%Since Jun 30 -22.79%
Weight 6.6%Value $56.92MPrice $429.21Shares 125K -7.41%Since Jun 30 -5.74%
Weight 6.4%Value $54.98MPrice $25.39Shares 2.10MSince Jun 30 -3.02%
Weight 6.3%Value $54.34MPrice $25.86Shares 1.50MSince Jun 30 -28.62%
Weight 6.1%Value $52.59MPrice $42.39Shares 1.09M +21.11%Since Jun 30 -12.15%
Weight 5.8%Value $49.50MPrice $175.87Shares 220K +33.33%Since Jun 30 -21.84%
Weight 5.0%Value $43.17MPrice $18.30Shares 1.50M -18.75%Since Jun 30 -36.41%
Weight 4.9%Value $42.24MPrice $40.69Shares 690K -12.23%Since Jun 30 -33.50%
Weight 4.7%Value $40.15MPrice $261.99Shares 135K -71.57%Since Jun 30 -11.90%
Weight 4.7%Value $39.84MPrice $60.94Shares 600KSince Jun 30 -8.22%
Weight 4.5%Value $38.91MPrice $16.14Shares 3.00MSince Jun 30 +24.44%
Weight 4.4%Value $38.07MPrice $6.96Shares 3.70MSince Jun 30 -32.36%
Weight 4.4%Value $37.76MPrice $90.93Shares 330KSince Jun 30 -20.52%
Weight 4.3%Value $36.62MPrice $6.21Shares 5.66M +9.69%Since Jun 30 -4.02%
Weight 3.8%Value $32.24MPrice $30.66Shares 810K +10.20%Since Jun 30 -22.95%
Weight 3.3%Value $28.64MPrice $41.74Shares 600KSince Jun 30 -12.57%
AERO-SWXNo ticker matchAdd
Weight 3.3%Value $28.46MShares 1.08M +30.42%
Weight 2.6%Value $22.32MPrice $7.42Shares 2.25MSince Jun 30 -25.05%
Weight 2.4%Value $20.93MPrice $18.21Shares 1.06MSince Jun 30 -7.38%
Weight 1.9%Value $16.65MPrice $14.06Shares 878KSince Jun 30 -25.88%
| Stock | Weight | Value | Since Jun 30 | Shares change | Action |
|---|---|---|---|---|---|
| 7.1% | $61.21M | -16.68% | — | Hold | |
| 7.1% | $60.78M | -22.79% | -12.73% | Trim | |
| 6.6% | $56.92M | -5.74% | -7.41% | Trim | |
| 6.4% | $54.98M | -3.02% | — | Hold | |
| 6.3% | $54.34M | -28.62% | — | New | |
| 6.1% | $52.59M | -12.15% | +21.11% | Add | |
| 5.8% | $49.50M | -21.84% | +33.33% | Add | |
| 5.0% | $43.17M | -36.41% | -18.75% | Trim | |
| 4.9% | $42.24M | -33.50% | -12.23% | Trim | |
| 4.7% | $40.15M | -11.90% | -71.57% | Trim | |
| 4.7% | $39.84M | -8.22% | — | New | |
| 4.5% | $38.91M | +24.44% | — | New | |
| 4.4% | $38.07M | -32.36% | — | Hold | |
| 4.4% | $37.76M | -20.52% | — | Hold | |
| 4.3% | $36.62M | -4.02% | +9.69% | Add | |
| 3.8% | $32.24M | -22.95% | +10.20% | Add | |
| 3.3% | $28.64M | -12.57% | — | New | |
| AERO-SWXNo ticker match | 3.3% | $28.46M | — | +30.42% | Add |
| 2.6% | $22.32M | -25.05% | — | New | |
| 2.4% | $20.93M | -7.38% | — | New | |
| 1.9% | $16.65M | -25.88% | — | New |
Weight is the share of the reported 13F value, including options at notional value. “Since Jun 30” compares the latest close with the quarter-end price implied by the filing (value ÷ shares).
Largest buys in 2026 Q2
Largest sells in 2026 Q2
Source: SEC Form 13F, values as reported by the filer. Filings lag up to 45 days after quarter end and cover only certain long positions. Research only, not investment advice.