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Disclosery

Hudson Bay Capital Management LP: BIIB position timeline

Available 13F reports, 13D and 13G stakes and each Form 3, 4 and 5 line of Hudson Bay Capital Management LP on BIIB, newest first. How the timeline and the estimate are built.

Hudson Bay Capital Management LP held 90,000 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 90,000 shares
    Change vs previous 13F -111,367 shares

    0.09% of the 13F portfolio, value $19,445,400.

    13F-HR 0001393825-26-000058 filed by Hudson Bay Capital Management 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 201,367 shares
    Change vs previous 13F -20,493 shares

    0.22% of the 13F portfolio, value $36,916,612.

    13F-HR 0001393825-26-000041 filed by Hudson Bay Capital Management 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 221,860 shares
    Change vs previous 13F -31,291 shares

    0.22% of the 13F portfolio, value $39,045,141.

    13F-HR 0001393825-26-000021 filed by Hudson Bay Capital Management 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/A 253,151 shares
    Change vs previous 13F -14,589 shares

    0.22% of the 13F portfolio, value $35,461,392.

    13F-HR/A 0001393825-25-000093 filed by Hudson Bay Capital Management 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/A 267,740 shares
    Change vs previous 13F +67,220 shares

    0.22% of the 13F portfolio, value $33,625,467.

    13F-HR/A 0001393825-25-000066 filed by Hudson Bay Capital Management 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 200,520 shares
    Change vs previous 13F -40,488 shares

    0.17% of the 13F portfolio, value $27,439,157.

    13F-HR 0001393825-25-000010 filed by Hudson Bay Capital Management 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 241,008 shares
    Change vs previous 13F -58,992 shares

    0.22% of the 13F portfolio, value $36,854,943.

    13F-HR 0002033916-25-000027 filed by Hudson Bay Capital Management 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 300,000 shares
    Change vs previous 13F not available

    0.4% of the 13F portfolio, value $58,152,000.

    13F-HR 0002033916-24-000083 filed by Hudson Bay Capital Management LP
    Filed (acceptance time not in the bulk data set), ingested

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