ACK Asset Management LLC 13F: Quarter-over-Quarter Portfolio Changes
ACK Asset Management LLC reported a disclosed portfolio value of approximately $801.1 million in its latest SEC Form 13F-HR filing for Q1 2026, up 0.6% quarter on quarter. Over the quarter, the fund initiated 3 new positions, bought more shares in 6 holdings, trimmed 1 holding, and exited 6 positions.
ACK Asset Management LLC's top buy was a new stake in Lfus (LFUS) , equal to 5.7% of the disclosed portfolio. Its top sell was Enersys (ENS) . The fund exited the position completely after it had accounted for 5.6% of the previous portfolio.
New PositionsQ1 2026
Securities disclosed for the first time in Q1 2026 that were not present in the prior 13F-HR filing.
Top BuysQ1 2026
The fund's top buys among existing positions in Q1 2026. Ranked by portfolio-weight impact, with the percentage of additional shares shown separately.
| Company | Ticker | Portfolio Weight Change | More Shares | History |
|---|---|---|---|---|
| AERO-SWX | MTASF | +2.7% | +436.0% | Holders → |
| MASTERBRAND INC | MBC | +0.7% | +60.9% | Holders → |
| CLFD | CLFD | +0.1% | +17.6% | Holders → |
| ROG | ROG | +1.3% | +8.8% | History → |
| DXP ENTERPRISES INC | DXPE | +1.2% | +8.3% | Holders → |
| CDNL | CDNL | +1.8% | +3.5% | Holders → |
Top SellsQ1 2026
The fund's top sells among positions it retained in Q1 2026. Ranked by portfolio-weight impact. Full exits are listed separately.
Full ExitsQ1 2026
Positions present in the prior 13F-HR filing that no longer appear in Q1 2026.
| Company | Ticker | Last-Reported Portfolio Weight |
|---|---|---|
| ENERSYS | ENS | 5.6% |
| ASTRONICS CORP | ATRO | 4.1% |
| ALBANY INTL CORP | AIN | 3.8% |
| APOGEE ENTERPRISES INC | APOG | 3.7% |
| ENERGY RECOVERY INC | ERII | 1.1% |
| CUSTOM TRUCK ONE SOURCE INC | CTOS | 0.6% |
Net Portfolio Value ChangeQ1 2026
- $0.8BPrior quarter
- $0.8BCurrent quarter
- +$0.0BNet delta
- +0.6%% change
Methodology & FAQ
How ACK Asset Management LLC Quarterly Changes Are Computed
All deltas are sourced from sequential SEC Form 13F-HR filings for ACK Asset Management LLC: each row joins the most recent filing against the immediately preceding quarterly filing for the same fund. Share-count changes reflect reported trading activity, while portfolio weights can also move because of market price changes. Portfolio weights are normalized to exclude listed options for comparability. A complete description — including how confidential treatment filings are handled — is documented in the Methodology.
What stocks did ACK Asset Management LLC buy in Q1 2026?
In Q1 2026, ACK Asset Management LLC initiated 3 new positions (LFUS (LFUS), CTS (CTS), SWIM (SWIM)); bought more shares of AERO-SWX (MTASF), MASTERBRAND INC (MBC), CLFD (CLFD), ROG (ROG), DXP ENTERPRISES INC (DXPE) — the largest 5 of 6 adds.
What stocks did ACK Asset Management LLC sell in Q1 2026?
In Q1 2026, ACK Asset Management LLC fully sold 6 positions (ENERSYS (ENS), ASTRONICS CORP (ATRO), ALBANY INTL CORP (AIN), APOGEE ENTERPRISES INC (APOG), ENERGY RECOVERY INC (ERII), CUSTOM TRUCK ONE SOURCE INC (CTOS)); reduced holdings in GVA (GVA).
Which positions did ACK Asset Management LLC initiate in Q1 2026?
ACK Asset Management LLC established 3 new positions in Q1 2026: LFUS (LFUS, 5.7%), CTS (CTS, 3.5%), SWIM (SWIM, 3.5%).
Which existing positions saw the largest allocation increases for ACK Asset Management LLC in Q1 2026?
Of 6 existing positions with share-count increases in Q1 2026, the largest were: AERO-SWX (MTASF, +2.7% weight, +436.0% shares), MASTERBRAND INC (MBC, +0.7% weight, +60.9% shares), CLFD (CLFD, +0.1% weight, +17.6% shares), ROG (ROG, +1.3% weight, +8.8% shares), DXP ENTERPRISES INC (DXPE, +1.2% weight, +8.3% shares), CDNL (CDNL, +1.8% weight, +3.5% shares).
Which positions did ACK Asset Management LLC fully exit in Q1 2026?
ACK Asset Management LLC fully exited 6 positions in Q1 2026: ENERSYS (ENS, last-reported weight 5.6%), ASTRONICS CORP (ATRO, last-reported weight 4.1%), ALBANY INTL CORP (AIN, last-reported weight 3.8%), APOGEE ENTERPRISES INC (APOG, last-reported weight 3.7%), ENERGY RECOVERY INC (ERII, last-reported weight 1.1%), CUSTOM TRUCK ONE SOURCE INC (CTOS, last-reported weight 0.6%).
Which existing positions saw the largest allocation reductions for ACK Asset Management LLC in Q1 2026?
Of 1 existing position with share-count reductions in Q1 2026, the largest were: GVA (GVA, -3.5% weight, -50.0% shares).
Do quarter-over-quarter 13F allocation changes constitute explicit trading signals?
No. Quarter-over-quarter changes reflect a combination of active trading and market price movement. A weight increase can result from price appreciation alone, without the manager adding shares. Share-count delta is the cleaner indicator of explicit trading activity. All deltas on this page are sourced from sequential SEC Form 13F-HR filings.