Skip to content
Disclosery

PRIMECAP MANAGEMENT CO/CA/: BIIB position timeline

Available 13F reports, 13D and 13G stakes and each Form 3, 4 and 5 line of PRIMECAP MANAGEMENT CO/CA/ on BIIB, newest first. How the timeline and the estimate are built.

PRIMECAP MANAGEMENT CO/CA/ held 15,154,606 BIIB shares at 2026-06-30 per its 13F-HR filed 2026-08-14.

the latest 13F is the newest step

  1. period ended2026-06-30
    13F 15,154,606 shares
    Change vs previous 13F +396,999 shares

    1.94% of the 13F portfolio, value $3,274,304,389.

    13F-HR 0000763212-26-000028 filed by PRIMECAP MANAGEMENT CO/CA/
    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 14,757,607 shares
    Change vs previous 13F -390 shares

    2.13% of the 13F portfolio, value $2,705,512,094.

    13F-HR 0000763212-26-000016 filed by PRIMECAP MANAGEMENT CO/CA/
    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 14,757,997 shares
    Change vs previous 13F -196,700 shares

    1.97% of the 13F portfolio, value $2,597,259,895.

    13F-HR 0000763212-26-000012 filed by PRIMECAP MANAGEMENT CO/CA/
    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 14,954,697 shares
    Change vs previous 13F -847,425 shares

    1.6% of the 13F portfolio, value $2,094,853,953.

    13F-HR 0000763212-25-000005 filed by PRIMECAP MANAGEMENT CO/CA/
    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 15,802,122 shares
    Change vs previous 13F -141,137 shares

    1.57% of the 13F portfolio, value $1,984,588,503.

    13F-HR 0001085146-25-004804 filed by PRIMECAP MANAGEMENT CO/CA/
    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 15,943,259 shares
    Change vs previous 13F -102,950 shares

    1.8% of the 13F portfolio, value $2,181,675,561.

    13F-HR 0001085146-25-002901 filed by PRIMECAP MANAGEMENT CO/CA/
    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 16,046,209 shares
    Change vs previous 13F -268,870 shares

    1.9% of the 13F portfolio, value $2,453,786,283.

    13F-HR 0001085146-25-000946 filed by PRIMECAP MANAGEMENT CO/CA/
    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 16,315,079 shares
    Change vs previous 13F not available

    2.33% of the 13F portfolio, value $3,162,514,912.

    13F-HR 0001085146-24-005460 filed by PRIMECAP MANAGEMENT CO/CA/
    Filed (acceptance time not in the bulk data set), ingested

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