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WESTFIELD CAPITAL MANAGEMENT CO LP: INSM position timeline

Available 13F reports, 13D and 13G stakes and each Form 3, 4 and 5 line of WESTFIELD CAPITAL MANAGEMENT CO LP on INSM, newest first. How the timeline and the estimate are built.

WESTFIELD CAPITAL MANAGEMENT CO LP held 1,629,561 INSM shares at 2026-06-30 per its 13F-HR filed 2026-08-12.

the latest 13F is the newest step

  1. period ended2026-06-30
    13F 1,629,561 shares
    Change vs previous 13F +161,102 shares

    0.57% of the 13F portfolio, value $173,743,795.

    13F-HR 0001177719-26-000021 filed by WESTFIELD CAPITAL MANAGEMENT CO LP
    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 1,468,459 shares
    Change vs previous 13F +1,035,938 shares

    1.01% of the 13F portfolio, value $240,122,429.

    13F-HR 0001177719-26-000018 filed by WESTFIELD CAPITAL MANAGEMENT CO LP
    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 432,521 shares
    Change vs previous 13F -55,406 shares

    0.31% of the 13F portfolio, value $75,275,955.

    13F-HR 0001177719-26-000005 filed by WESTFIELD CAPITAL MANAGEMENT CO LP
    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 487,927 shares
    Change vs previous 13F -851,361 shares

    0.29% of the 13F portfolio, value $70,266,367.

    13F-HR 0001177719-25-000003 filed by WESTFIELD CAPITAL MANAGEMENT CO LP
    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 1,339,288 shares
    Change vs previous 13F -67,321 shares

    0.57% of the 13F portfolio, value $134,785,944.

    13F-HR 0001085146-25-004820 filed by WESTFIELD CAPITAL MANAGEMENT CO LP
    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 1,406,609 shares
    Change vs previous 13F +468,058 shares

    0.52% of the 13F portfolio, value $107,310,201.

    13F-HR 0001085146-25-002864 filed by WESTFIELD CAPITAL MANAGEMENT CO LP
    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 938,551 shares
    Change vs previous 13F +686,812 shares

    0.28% of the 13F portfolio, value $64,797,561.

    13F-HR 0001085146-25-000986 filed by WESTFIELD CAPITAL MANAGEMENT CO LP
    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 251,739 shares
    Change vs previous 13F not available

    0.08% of the 13F portfolio, value $18,376,947.

    13F-HR 0001085146-24-005556 filed by WESTFIELD CAPITAL MANAGEMENT CO LP
    Filed (acceptance time not in the bulk data set), ingested

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