ACK Asset Management LLC
Long book
$801.1M
Q1 2026
Positions
20
Top-10 weight
62%
concentration
Last quarter
+25.4%
SPY +14.8%
Turnover
35%
of book per quarter
Strategy in plain words
auto-generated from filingsACK Asset Management LLC is a concentrated fundamental stock-picker, running a $801.1M US long book across 20 positions.
The portfolio is concentrated: the top 10 names carry 62% of the portfolio. The portfolio is actively managed, with meaningful quarterly turnover. Current anchor positions: MATERION CORP, ADVANCED DRAINAGE SYSTEMS IN, ATS CORP, ROGERS CORP, HELIOS TECHNOLOGIES INC.
Over the last 9 quarters its long book ran on average 2.1pp per quarter ahead of the S&P 500, beating the index in 5 of 9 quarters. We rate its filings as signal-bearing: position changes reflect genuine views.
Implied long-book return vs S&P 500
methodology: positions priced quarterly, no shorts/options Fund long book S&P 500
Q1 2024
-5.8%
Q2 2024
+1.5%
Q3 2024
-0.4%
Q4 2024
-11.6%
Q1 2025
+27.1%
Q2 2025
+12.8%
Q3 2025
+3.8%
Q4 2025
+6.4%
Q1 2026
+25.4%
Sector allocation
Industrials 53%
Consumer discretionary 16%
Other 14%
Technology 11%
Materials 6%
Long book by quarter
What does ACK Asset own?
Q1 2026 13F| Company | Sector | Shares | Value | % of book | Change |
|---|---|---|---|---|---|
| MTRN MATERION CORP | Industrials | 474.8K | $68.7M | 8.6% | Held |
| WMS ADVANCED DRAINAGE SYSTEMS IN | Other | 390.0K | $53.5M | 6.7% | Held |
| ATS ATS CORP | Industrials | 1.8M | $52.1M | 6.5% | Held |
| ROG ROGERS CORP | Materials | 475.0K | $51.0M | 6.4% | +8.8% |
| HLIO HELIOS TECHNOLOGIES INC | Industrials | 780.4K | $50.5M | 6.3% | Held |
| LFUS LITTELFUSE INC | Industrials | 135.0K | $45.8M | 5.7% | New |
| CNM CORE & MAIN INC-CLASS A | Consumer discretionary | 900.0K | $44.5M | 5.5% | Held |
| NOVT NOVANTA INC | Technology | 375.0K | $44.3M | 5.5% | Held |
| SITE SITEONE LANDSCAPE SUPPLY INC | Consumer discretionary | 330.0K | $43.9M | 5.5% | Held |
| ASTE ASTEC INDUSTRIES INC | Industrials | 786.5K | $42.3M | 5.3% | Held |
| JHX JAMES HARDIE IND PLC | Industrials | 2.1M | $39.8M | 5.0% | Held |
| DXPE DXP ENTERPRISES INC | Consumer discretionary | 260.0K | $36.3M | 4.5% | +8.3% |
| CDNL CARDINAL INFRASTRUCTURE GR-A | Industrials | 874.0K | $34.7M | 4.3% | +3.5% |
| EXP EAGLE MATERIALS INC | Industrials | 165.0K | $31.3M | 3.9% | Held |
| MBC MASTERBRAND INC | Other | 3.7M | $30.7M | 3.8% | +60.9% |
| GVA GRANITE CONSTRUCTION INC | Industrials | 250.0K | $30.0M | 3.7% | -50.0% |
| CTS CTS CORP | Technology | 584.0K | $27.9M | 3.5% | New |
| SWIM LATHAM GROUP INC | Other | 5.2M | $27.7M | 3.5% | New |
| AERO MONTANA AEROSPACE AG | Industrials | 830.0K | $26.8M | 3.3% | +436.0% |
| CLFD CLEARFIELD INC | Technology | 735.2K | $19.5M | 2.4% | +17.6% |
13F filing history
| Period | Form | Filed | Entries | Reported value | Flags | Source |
|---|---|---|---|---|---|---|
| Q1 2026 | 13F-HR | May 15, 2026 | 20 | $801.1M | canonical | SEC ↗ |
| Q4 2025 | 13F-HR | Feb 13, 2026 | 23 | $796.8M | canonical | SEC ↗ |
| Q3 2025 | 13F-HR | Nov 14, 2025 | 20 | $799.1M | canonical | SEC ↗ |
| Q2 2025 | 13F-HR | Aug 13, 2025 | 21 | $761.4M | canonical | SEC ↗ |
| Q1 2025 | 13F-HR | May 13, 2025 | 20 | $609.0M | canonical | SEC ↗ |
| Q4 2024 | 13F-HR | Feb 13, 2025 | 22 | $746.4M | canonical | SEC ↗ |
| Q3 2024 | 13F-HR | Nov 13, 2024 | 18 | $809.2M | canonical | SEC ↗ |
| Q2 2024 | 13F-HR | Aug 13, 2024 | 19 | $810.3M | canonical | SEC ↗ |
| Q1 2024 | 13F-HR | May 14, 2024 | 20 | $858.3M | canonical | SEC ↗ |
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