Skip to content
Disclosery

Portolan Capital Management, LLC: BIIB position timeline

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

Portolan Capital Management, LLC held 142,856 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 142,856 shares
    Change vs previous 13F +24,375 shares

    1.16% of the 13F portfolio, value $30,865,467.

    13F-HR 0001104659-26-096980 filed by Portolan Capital Management, LLC
    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 118,481 shares
    Change vs previous 13F +33,491 shares

    1.16% of the 13F portfolio, value $21,721,122.

    13F-HR 0001104659-26-062488 filed by Portolan Capital Management, LLC
    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 84,990 shares
    Change vs previous 13F not available

    0.8% of the 13F portfolio, value $14,957,390.

    13F-HR 0001104659-26-016304 filed by Portolan Capital Management, LLC
    Filed (acceptance time not in the bulk data set), ingested

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