13-F holdings, Q2 2026
ACK Asset Management LLC
A 13-F is the report large US investment managers file with the SEC each quarter, listing the stocks they held at quarter end.
- Reported value
- $856.3M
- Positions
- 21
- Filed
- Data as of
These holdings are as of , 133 days ago.
13-Fs for Q3 2026 are due by .
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Top holdings
- WMS$61.2M390,000 shares7.1% of the book
- HLIO$60.8M681,000 shares7.1% of the book
- LFUS$56.9M125,000 shares6.6% of the book
- JHX$55M2,100,000 shares6.4% of the book
- GTX$54.3M1,500,000 shares6.3% of the book
- CNM$52.6M1,090,000 shares6.1% of the book
- EXP$49.5M220,000 shares5.8% of the book
- ATS$43.2M1,500,000 shares5% of the book
- ASTE$42.2M690,276 shares4.9% of the book
- MTRN$40.1M135,000 shares4.7% of the book
What changed this quarter
7 new positions and 6 sold out, against Q1 2026. Added and trimmed positions use the change in split-adjusted shares at the Q2 2026 implied price; full exits use their Q1 2026 reported value, not sale proceeds.
Largest buys
- GTX
GTX
+$54.3M
New
Your stake and evidence for GTX
What it means for you
This public view does not read your holdings or watchlist; open the member view to check your stake.
Use this to decide what to research, rather than as an instruction to copy a trade.
What happened
A position newly appears in the Q2 2026 book.
Displayed change: +$54.3M. The current book reports 1,500,000 shares.
Why it can matter
A change between quarter-end disclosures can prompt a question about the manager's exposure. It does not reveal the trade date, the execution price or why the position changed; a full exit is not proof of a bearish decision.
How we got this
A new position uses its current quarter's reported dollar value; this is not the amount spent buying it.
Comparable books exclude identified CUSIP, share-basis and new-security events from trades. Exit-size bands describe prior book weight, not the manager's intent.
Where the data comes from
SEC 13F quarter-end holdings for Q1 2026 and Q2 2026; these delayed disclosures omit shorts and many other assets.
Current source filed .
Technical details
Reported dollar change: 54345000 USD. Current reported shares: 1500000. Prior shares on current basis: not recorded.
- BWA
BWA
+$39.8M
New
Your stake and evidence for BWA
What it means for you
This public view does not read your holdings or watchlist; open the member view to check your stake.
Use this to decide what to research, rather than as an instruction to copy a trade.
What happened
A position newly appears in the Q2 2026 book.
Displayed change: +$39.8M. The current book reports 600,000 shares.
Why it can matter
A change between quarter-end disclosures can prompt a question about the manager's exposure. It does not reveal the trade date, the execution price or why the position changed; a full exit is not proof of a bearish decision.
How we got this
A new position uses its current quarter's reported dollar value; this is not the amount spent buying it.
Comparable books exclude identified CUSIP, share-basis and new-security events from trades. Exit-size bands describe prior book weight, not the manager's intent.
Where the data comes from
SEC 13F quarter-end holdings for Q1 2026 and Q2 2026; these delayed disclosures omit shorts and many other assets.
Current source filed .
Technical details
Reported dollar change: 39840000 USD. Current reported shares: 600000. Prior shares on current basis: not recorded.
- DNOW
DNOW
+$38.9M
New
Your stake and evidence for DNOW
What it means for you
This public view does not read your holdings or watchlist; open the member view to check your stake.
Use this to decide what to research, rather than as an instruction to copy a trade.
What happened
A position newly appears in the Q2 2026 book.
Displayed change: +$38.9M. The current book reports 3,000,000 shares.
Why it can matter
A change between quarter-end disclosures can prompt a question about the manager's exposure. It does not reveal the trade date, the execution price or why the position changed; a full exit is not proof of a bearish decision.
How we got this
A new position uses its current quarter's reported dollar value; this is not the amount spent buying it.
Comparable books exclude identified CUSIP, share-basis and new-security events from trades. Exit-size bands describe prior book weight, not the manager's intent.
Where the data comes from
SEC 13F quarter-end holdings for Q1 2026 and Q2 2026; these delayed disclosures omit shorts and many other assets.
Current source filed .
Technical details
Reported dollar change: 38910000 USD. Current reported shares: 3000000. Prior shares on current basis: not recorded.
- ST
ST
+$28.6M
New
Your stake and evidence for ST
What it means for you
This public view does not read your holdings or watchlist; open the member view to check your stake.
Use this to decide what to research, rather than as an instruction to copy a trade.
What happened
A position newly appears in the Q2 2026 book.
Displayed change: +$28.6M. The current book reports 600,000 shares.
Why it can matter
A change between quarter-end disclosures can prompt a question about the manager's exposure. It does not reveal the trade date, the execution price or why the position changed; a full exit is not proof of a bearish decision.
How we got this
A new position uses its current quarter's reported dollar value; this is not the amount spent buying it.
Comparable books exclude identified CUSIP, share-basis and new-security events from trades. Exit-size bands describe prior book weight, not the manager's intent.
Where the data comes from
SEC 13F quarter-end holdings for Q1 2026 and Q2 2026; these delayed disclosures omit shorts and many other assets.
Current source filed .
Technical details
Reported dollar change: 28644000 USD. Current reported shares: 600000. Prior shares on current basis: not recorded.
- SHLS
SHLS
+$22.3M
New
Your stake and evidence for SHLS
What it means for you
This public view does not read your holdings or watchlist; open the member view to check your stake.
Use this to decide what to research, rather than as an instruction to copy a trade.
What happened
A position newly appears in the Q2 2026 book.
Displayed change: +$22.3M. The current book reports 2,255,000 shares.
Why it can matter
A change between quarter-end disclosures can prompt a question about the manager's exposure. It does not reveal the trade date, the execution price or why the position changed; a full exit is not proof of a bearish decision.
How we got this
A new position uses its current quarter's reported dollar value; this is not the amount spent buying it.
Comparable books exclude identified CUSIP, share-basis and new-security events from trades. Exit-size bands describe prior book weight, not the manager's intent.
Where the data comes from
SEC 13F quarter-end holdings for Q1 2026 and Q2 2026; these delayed disclosures omit shorts and many other assets.
Current source filed .
Technical details
Reported dollar change: 22324500 USD. Current reported shares: 2255000. Prior shares on current basis: not recorded.
Largest sells
- MTRN
MTRN
−$101.1M
-71.6% shares
Your stake and evidence for MTRN
What it means for you
This public view does not read your holdings or watchlist; open the member view to check your stake.
Use this to decide what to research, rather than as an instruction to copy a trade.
What happened
Reported shares decreased between Q1 2026 and Q2 2026.
Displayed change: −$101.1M. The current book reports 135,000 shares.
Why it can matter
A change between quarter-end disclosures can prompt a question about the manager's exposure. It does not reveal the trade date, the execution price or why the position changed; a full exit is not proof of a bearish decision.
How we got this
For an added or trimmed position, subtract split-adjusted prior shares from current shares, then multiply by the current book's reported value per share; this is not the execution price.
135,000 current shares − 474,800 prior shares on the same basis = -339,800 shares.
Comparable books exclude identified CUSIP, share-basis and new-security events from trades. Exit-size bands describe prior book weight, not the manager's intent.
Where the data comes from
SEC 13F quarter-end holdings for Q1 2026 and Q2 2026; these delayed disclosures omit shorts and many other assets.
Current source filed .
Technical details
Reported dollar change: -101053122 USD. Current reported shares: 135000. Prior shares on current basis: 474800.
- ROG
ROG
−$51M
Sold out, was 6.4% of the book
Your stake and evidence for ROG
What it means for you
This public view does not read your holdings or watchlist; open the member view to check your stake.
Use this to decide what to research, rather than as an instruction to copy a trade.
What happened
The position reported in Q1 2026 is absent from the comparable Q2 2026 book.
Displayed change: −$51M. This was 6.4% of the prior book.
Why it can matter
A change between quarter-end disclosures can prompt a question about the manager's exposure. It does not reveal the trade date, the execution price or why the position changed; a full exit is not proof of a bearish decision.
How we got this
A full exit is shown as the negative of its prior reported value, not sale proceeds or a value at today's price.
Comparable books exclude identified CUSIP, share-basis and new-security events from trades. Exit-size bands describe prior book weight, not the manager's intent.
Where the data comes from
SEC 13F quarter-end holdings for Q1 2026 and Q2 2026; these delayed disclosures omit shorts and many other assets.
Current source filed .
Technical details
Reported dollar change: -50982000 USD. Current reported shares: not recorded. Prior shares on current basis: 475000.
- NOVT
NOVT
−$44.3M
Sold out, was 5.5% of the book
Your stake and evidence for NOVT
What it means for you
This public view does not read your holdings or watchlist; open the member view to check your stake.
Use this to decide what to research, rather than as an instruction to copy a trade.
What happened
The position reported in Q1 2026 is absent from the comparable Q2 2026 book.
Displayed change: −$44.3M. This was 5.5% of the prior book.
Why it can matter
A change between quarter-end disclosures can prompt a question about the manager's exposure. It does not reveal the trade date, the execution price or why the position changed; a full exit is not proof of a bearish decision.
How we got this
A full exit is shown as the negative of its prior reported value, not sale proceeds or a value at today's price.
Comparable books exclude identified CUSIP, share-basis and new-security events from trades. Exit-size bands describe prior book weight, not the manager's intent.
Where the data comes from
SEC 13F quarter-end holdings for Q1 2026 and Q2 2026; these delayed disclosures omit shorts and many other assets.
Current source filed .
Technical details
Reported dollar change: -44291000 USD. Current reported shares: not recorded. Prior shares on current basis: 375000.
- DXPE
DXPE
−$36.3M
Sold out, was 4.5% of the book
Your stake and evidence for DXPE
What it means for you
This public view does not read your holdings or watchlist; open the member view to check your stake.
Use this to decide what to research, rather than as an instruction to copy a trade.
What happened
The position reported in Q1 2026 is absent from the comparable Q2 2026 book.
Displayed change: −$36.3M. This was 4.5% of the prior book.
Why it can matter
A change between quarter-end disclosures can prompt a question about the manager's exposure. It does not reveal the trade date, the execution price or why the position changed; a full exit is not proof of a bearish decision.
How we got this
A full exit is shown as the negative of its prior reported value, not sale proceeds or a value at today's price.
Comparable books exclude identified CUSIP, share-basis and new-security events from trades. Exit-size bands describe prior book weight, not the manager's intent.
Where the data comes from
SEC 13F quarter-end holdings for Q1 2026 and Q2 2026; these delayed disclosures omit shorts and many other assets.
Current source filed .
Technical details
Reported dollar change: -36330000 USD. Current reported shares: not recorded. Prior shares on current basis: 260000.
- CDNL
CDNL
−$34.7M
Sold out, was 4.3% of the book
Your stake and evidence for CDNL
What it means for you
This public view does not read your holdings or watchlist; open the member view to check your stake.
Use this to decide what to research, rather than as an instruction to copy a trade.
What happened
The position reported in Q1 2026 is absent from the comparable Q2 2026 book.
Displayed change: −$34.7M. This was 4.3% of the prior book.
Why it can matter
A change between quarter-end disclosures can prompt a question about the manager's exposure. It does not reveal the trade date, the execution price or why the position changed; a full exit is not proof of a bearish decision.
How we got this
A full exit is shown as the negative of its prior reported value, not sale proceeds or a value at today's price.
Comparable books exclude identified CUSIP, share-basis and new-security events from trades. Exit-size bands describe prior book weight, not the manager's intent.
Where the data comes from
SEC 13F quarter-end holdings for Q1 2026 and Q2 2026; these delayed disclosures omit shorts and many other assets.
Current source filed .
Technical details
Reported dollar change: -34658000 USD. Current reported shares: not recorded. Prior shares on current basis: 874000.
What was sold out, by size
- 6 real positions, 0.25% of the book or more
All of this comes from the filer's public SEC filings. A 13-F shows long positions in US-listed securities at quarter end and can leave out short positions, cash and non-US holdings, so it is not the whole portfolio. This is filing data, not investment advice.