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BLAIR WILLIAM & CO/IL: AON position timeline

Available 13F reports, 13D and 13G stakes and each Form 3, 4 and 5 line of BLAIR WILLIAM & CO/IL on AON, newest first. How the timeline and the estimate are built.

BLAIR WILLIAM & CO/IL held 360,607 AON shares at 2026-06-30 per its 13F-HR filed 2026-08-11.

the latest 13F is the newest step

  1. period ended2026-06-30
    13F 360,607 shares
    Change vs previous 13F -60,998 shares

    0.31% of the 13F portfolio, value $119,609,713.

    13F-HR 0001104659-26-093821 filed by BLAIR WILLIAM & CO/IL
    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 421,605 shares
    Change vs previous 13F -74,702 shares

    0.39% of the 13F portfolio, value $136,085,646.

    13F-HR 0001104659-26-057897 filed by BLAIR WILLIAM & CO/IL
    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 496,307 shares
    Change vs previous 13F -33,466 shares

    0.47% of the 13F portfolio, value $175,136,806.

    13F-HR 0001104659-26-015563 filed by BLAIR WILLIAM & CO/IL
    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 529,773 shares
    Change vs previous 13F -38,214 shares

    0.5% of the 13F portfolio, value $188,906,550.

    13F-HR 0001104659-25-109927 filed by BLAIR WILLIAM & CO/IL
    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 567,987 shares
    Change vs previous 13F +13,237 shares

    0.56% of the 13F portfolio, value $202,634,886.

    13F-HR 0001104659-25-070274 filed by BLAIR WILLIAM & CO/IL
    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 554,750 shares
    Change vs previous 13F -9,497 shares

    0.67% of the 13F portfolio, value $221,395,350.

    13F-HR 0001104659-25-046545 filed by BLAIR WILLIAM & CO/IL
    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 564,247 shares
    Change vs previous 13F -28,303 shares

    0.59% of the 13F portfolio, value $202,654,837.

    13F-HR 0001104659-25-011872 filed by BLAIR WILLIAM & CO/IL
    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 592,550 shares
    Change vs previous 13F not available

    0.6% of the 13F portfolio, value $205,016,439.

    13F-HR 0001104659-24-116499 filed by BLAIR WILLIAM & CO/IL
    Filed (acceptance time not in the bulk data set), ingested

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