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Disclosery

WILLIAM BLAIR INVESTMENT MANAGEMENT, LLC: ATAT position timeline

Available 13F reports, 13D and 13G stakes and each Form 3, 4 and 5 line of WILLIAM BLAIR INVESTMENT MANAGEMENT, LLC on ATAT, newest first. How the timeline and the estimate are built.

WILLIAM BLAIR INVESTMENT MANAGEMENT, LLC held 0 ATAT shares at 2026-03-31 per its 13F-HR filed 2026-05-08.

the latest 13F is the newest step

  1. period ended2026-03-31
    13F 0 shares
    Change vs previous 13F -255,330 shares

    13F-HR 0001644956-26-000021 filed by WILLIAM BLAIR INVESTMENT MANAGEMENT, LLC
    Filed (acceptance time not in the bulk data set), ingested

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

    Exited: the 13F for this period no longer lists the position.

  2. period ended2025-12-31
    13F 255,330 shares
    Change vs previous 13F +65,849 shares

    0.03% of the 13F portfolio, value $10,060,002.

    13F-HR 0001644956-26-000007 filed by WILLIAM BLAIR INVESTMENT 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 ended2025-09-30
    13F 189,481 shares
    Change vs previous 13F +189,481 shares

    0.02% of the 13F portfolio, value $7,122,591.

    13F-HR 0001644956-25-000045 filed by WILLIAM BLAIR INVESTMENT MANAGEMENT, LLC
    Filed (acceptance time not in the bulk data set), ingested

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

  4. period ended2025-06-30
    13F 0 shares
    Change vs previous 13F -1,639,155 shares

    13F-HR 0001644956-25-000032 filed by WILLIAM BLAIR INVESTMENT MANAGEMENT, LLC
    Filed (acceptance time not in the bulk data set), ingested

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

    Exited: the 13F for this period no longer lists the position.

  5. period ended2025-03-31
    13F 1,639,155 shares
    Change vs previous 13F +730,463 shares

    0.13% of the 13F portfolio, value $46,471,167.

    13F-HR 0001644956-25-000018 filed by WILLIAM BLAIR INVESTMENT MANAGEMENT, LLC
    Filed (acceptance time not in the bulk data set), ingested

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

  6. period ended2024-12-31
    13F 908,692 shares
    Change vs previous 13F not available

    0.06% of the 13F portfolio, value $24,433,215.

    13F-HR 0001644956-25-000002 filed by WILLIAM BLAIR INVESTMENT MANAGEMENT, LLC
    Filed (acceptance time not in the bulk data set), ingested

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