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WESTFIELD CAPITAL MANAGEMENT CO LP: RKLB position timeline

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

WESTFIELD CAPITAL MANAGEMENT CO LP held 2,114,005 RKLB 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 2,114,005 shares
    Change vs previous 13F -1,058,606 shares

    0.7% of the 13F portfolio, value $214,888,621.

    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 3,172,611 shares
    Change vs previous 13F +580,168 shares

    0.85% of the 13F portfolio, value $203,745,048.

    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 2,592,443 shares
    Change vs previous 13F +154,623 shares

    0.75% of the 13F portfolio, value $180,848,824.

    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 2,437,820 shares
    Change vs previous 13F +72,772 shares

    0.49% of the 13F portfolio, value $116,795,956.

    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 2,365,048 shares
    Change vs previous 13F not available

    0.35% of the 13F portfolio, value $84,597,767.

    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).