Investor
ACK Asset Management LLC
CIK 0001510940 · filed 2026-05-15 · SEC filing
13F book
$801.1M
Positions
20
3 new · 6 sold
Largest name
8.6%
Materion Corp · MTRN
Est. mark
$38.2M
Price effect on 17 names still held. Flow −$33.8M.
| Name | Ticker | Shares | Value | Weight | Est. mark | Change |
|---|---|---|---|---|---|---|
| Materion Corp | MTRN | 474.8K | $68.7M | 8.6% | $9.65M | Held |
| Advanced Drain Sys Inc Del | — | 390K | $53.5M | 6.7% | −$3M | Held |
| Ats Corporation | — | 1.85M | $52.1M | 6.5% | $1.22M | Held |
| Rogers Corp | ROG | 475K | $51M | 6.4% | $6.88M | Added$11M |
| Helios Technologies, Inc. | HLIO | 780.4K | $50.5M | 6.3% | $8.76M | Held |
| Littelfuse Inc | — | 135K | $45.8M | 5.7% | — | New |
| Core & Main, Inc. | CNM | 900K | $44.5M | 5.5% | −$2.31M | Held |
| Novanta Inc | — | 375K | $44.3M | 5.5% | −$330K | Held |
| SiteOne Landscape Supply, Inc. | SITE | 330K | $43.9M | 5.5% | $2.82M | Held |
| Astec Inds Inc | — | 786.5K | $42.3M | 5.3% | $8.27M | Held |
| James Hardie Inds Plc | — | 2.1M | $39.8M | 5.0% | −$3.8M | Held |
| Dxp Enterprises Inc | DXPE | 260K | $36.3M | 4.5% | $7.19M | Added$9.98M |
| Cardinal Infrastructure Grou | — | 874K | $34.7M | 4.3% | $13.1M | Added$14.2M |
| Eagle Matls Inc | — | 165K | $31.3M | 3.9% | −$2.84M | Held |
| MasterBrand, Inc. | MBC | 3.7M | $30.7M | 3.8% | −$6.28M | Added$5.36M |
| Granite Constr Inc | — | 250K | $30M | 3.7% | $1.13M | Cut−$27.7M |
| Cts Corp | CTS | 584K | $27.9M | 3.5% | — | New |
| Latham Group, Inc. | SWIM | 5.16M | $27.7M | 3.5% | — | New |
| Aero-Swx | — | 830K | $26.8M | 3.3% | −$525.6K | Added$21.3M |
| Clearfield, Inc. | CLFD | 735.2K | $19.5M | 2.4% | −$1.68M | Added$1.24M |
Positions as of Q1 2026. 13F filings arrive up to 45 days after quarter-end and omit shorts. Values are quarter-end marks, as filed. Estimated mark is the price effect on shares still held — not realized P&L or investment advice.