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SEC Form 13F

ACK Asset Management LLC 13F Holdings

Inspect ACK Asset Management LLC's 2026-06-30 SEC 13F positions, public filing date, amendments and original receipt.

As of 2026-08-14T03:59:59.999Z

Report period
2026-06-30
Publicly available
2026-08-14
Reported value
$856,327,037
Positions
21
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Disclosed positions

Largest disclosed position values

Scale: 0 to 61,214,000 USD · zero baseline

Largest disclosed position values

  • WMS · COM+61,214,400 USD
  • HLIO · COM+60,779,250 USD
  • LFUS · COM+56,916,250 USD
  • JHX · COM+54,978,000 USD
  • GTX · COM+54,345,000 USD
  • CNM · COM+52,592,500 USD
  • EXP · COM+49,500,000 USD
  • ATS · COM+43,170,000 USD
  • ASTE · COM+42,237,988 USD
  • MTRN · COM+40,147,650 USD

Reported underlying-position values for 2026-06-30, publicly available 2026-08-14. Put/call values are not option premiums; this subset is not a complete portfolio allocation. Exact issuer, class and unit remain in the table. Showing the first 10 of 21 recorded values; the complete table remains available below.

Inspect all 21 displayed rows: Disclosed positions

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WMSWMSCOM$61,214,400390,000SHNone
HLIOHLIOCOM$60,779,250681,000SHNone
LFUSLFUSCOM$56,916,250125,000SHNone
JHXJHXCOM$54,978,0002,100,000SHNone
GTXGTXCOM$54,345,0001,500,000SHNone
CNMCNMCOM$52,592,5001,090,000SHNone
EXPEXPCOM$49,500,000220,000SHNone
ATSATSCOM$43,170,0001,500,000SHNone
ASTEASTECOM$42,237,988690,276SHNone
MTRNMTRNCOM$40,147,650135,000SHNone
BWABWACOM$39,840,000600,000SHNone
DNOWDNOWCOM$38,910,0003,000,000SHNone
MBCMBCCOM$38,073,0003,700,000SHNone
SITESITECOM$37,755,300330,000SHNone
SWIMSWIMCOM$36,620,2005,660,000SHNone
CLFDCLFDCOM$32,237,858810,200SHNone
STSTCOM$28,644,000600,000SHNone
AERO-SWXUnresolvedCOM$28,460,4081,082,500SHNone
SHLSSHLSCOM$22,324,5002,255,000SHNone
EQPTEQPTCOM$20,934,5581,064,830SHNone
MEIMEICOM$16,646,175877,500SHNone

Largest 50 positions by reported value; the filing may contain more positions.

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WMSWMSCOM$61,214,400390,000SHNone

First displayed source row from Disclosed positions. The full bounded history and coverage notes remain below.

The displayed observation date is 2026-06-30 and its public availability date is 2026-08-14. Subtracting those calendar dates gives 45 days of disclosure lag. Historical public research can use the record from the availability date, rather than backdating knowledge to the observation date. The calendar-day difference does not assert an intraday publication time.

Read the amount together with its Unit and Option columns. A reported put or call position is not an option premium paid, and a quarterly holding is not a purchase made on its public filing date. Check every accession in the effective amendment lineage below: a retained holding can originate in an earlier filing rather than the latest linked amendment.

Open the linked original receipts to verify the row, then inspect a second record before drawing a pattern. This public filing observation supplies source evidence, not a completed copy-trading return.

How amendments affect these holdings

This view uses 1 effective filing version(s). A restatement replaces the previous book; a new-holdings amendment adds positions. 1 positions lack a resolved ticker and 0 positions are put or call entries.

The displayed holdings combine the effective filing versions listed here. The latest receipt linked below identifies the current projection version; it is not proof that every retained holding originated in that latest amendment. Inspect all effective accessions when verifying a position's source.

A 13F is a delayed quarterly snapshot of disclosed holdings. It is not a complete trade ledger and does not reveal every position in a manager's portfolio. Option values refer to the reported underlying position rather than a traded option premium.

Show the table · 1 row, 2 columns
Effective SEC accessionRole in this view
0001510940-26-000005Latest effective version

Quarter end and public filing date

Use the filing's public availability date when constructing a historical observation. The quarter-end report period is earlier and cannot be substituted for when the public learned the holdings.