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WESTFIELD CAPITAL MANAGEMENT CO LP: ONTO position timeline

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

WESTFIELD CAPITAL MANAGEMENT CO LP held 299,383 ONTO 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 299,383 shares
    Change vs previous 13F -27,577 shares

    0.37% of the 13F portfolio, value $113,301,496.

    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 326,960 shares
    Change vs previous 13F -156,122 shares

    0.28% of the 13F portfolio, value $67,049,687.

    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 483,082 shares
    Change vs previous 13F +8,552 shares

    0.32% of the 13F portfolio, value $76,259,325.

    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 474,530 shares
    Change vs previous 13F +123,466 shares

    0.26% of the 13F portfolio, value $61,318,767.

    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 351,064 shares
    Change vs previous 13F +147,498 shares

    0.15% of the 13F portfolio, value $35,432,890.

    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 203,566 shares
    Change vs previous 13F -76,617 shares

    0.12% of the 13F portfolio, value $24,700,698.

    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 280,183 shares
    Change vs previous 13F not available

    0.2% of the 13F portfolio, value $46,698,101.

    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).