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Disclosery

ACK Asset Management LLC: MTRN position timeline

Available 13F reports, 13D and 13G stakes and each Form 3, 4 and 5 line of ACK Asset Management LLC on MTRN, newest first. How the timeline and the estimate are built.

ACK Asset Management LLC held 135,000 MTRN shares at 2026-06-30 per its 13F-HR filed 2026-08-13.

the latest 13F is the newest step

  1. period ended2026-06-30
    13F 135,000 shares
    Change vs previous 13F -339,800 shares

    4.69% of the 13F portfolio, value $40,147,650.

    13F-HR 0001510940-26-000005 filed by ACK Asset Management LLC
    Filed (acceptance time not in the bulk data set), ingested

    Acceptance time not in the bulk data set (spec §4.2).

  2. period ended2026-03-31
    13F 474,800 shares
    Change vs previous 13F 0 shares

    8.57% of the 13F portfolio, value $68,679,820.

    13F-HR 0001510940-26-000004 filed by ACK Asset Management LLC
    Filed (acceptance time not in the bulk data set), ingested

    Acceptance time not in the bulk data set (spec §4.2).

  3. period ended2025-12-31
    13F 474,800 shares
    Change vs previous 13F -50,000 shares

    7.41% of the 13F portfolio, value $59,027,136.

    13F-HR 0001510940-26-000001 filed by ACK Asset Management LLC
    Filed (acceptance time not in the bulk data set), ingested

    Acceptance time not in the bulk data set (spec §4.2).

  4. period ended2025-09-30
    13F 524,800 shares
    Change vs previous 13F 0 shares

    7.93% of the 13F portfolio, value $63,401,088.

    13F-HR 0001510940-25-000006 filed by ACK Asset Management LLC
    Filed (acceptance time not in the bulk data set), ingested

    Acceptance time not in the bulk data set (spec §4.2).

  5. period ended2025-06-30
    13F 524,800 shares
    Change vs previous 13F +65,600 shares

    5.47% of the 13F portfolio, value $41,653,376.

    13F-HR 0001510940-25-000005 filed by ACK Asset Management LLC
    Filed (acceptance time not in the bulk data set), ingested

    Acceptance time not in the bulk data set (spec §4.2).

  6. period ended2025-03-31
    13F 459,200 shares
    Change vs previous 13F -35,600 shares

    6.15% of the 13F portfolio, value $37,470,720.

    13F-HR 0001510940-25-000002 filed by ACK Asset Management LLC
    Filed (acceptance time not in the bulk data set), ingested

    Acceptance time not in the bulk data set (spec §4.2).

  7. period ended2024-12-31
    13F 494,800 shares
    Change vs previous 13F -10,700 shares

    6.55% of the 13F portfolio, value $48,925,824.

    13F-HR 0000899140-25-000241 filed by ACK Asset Management LLC
    Filed (acceptance time not in the bulk data set), ingested

    Acceptance time not in the bulk data set (spec §4.2).

  8. period ended2024-09-30
    13F 505,500 shares
    Change vs previous 13F not available

    6.99% of the 13F portfolio, value $56,545,230.

    13F-HR 0000899140-24-001197 filed by ACK Asset Management LLC
    Filed (acceptance time not in the bulk data set), ingested

    Acceptance time not in the bulk data set (spec §4.2).