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MAD RIVER INVESTORS: BRK-B position timeline

Available 13F reports, 13D and 13G stakes and each Form 3, 4 and 5 line of MAD RIVER INVESTORS on BRK-B, newest first. How the timeline and the estimate are built.

MAD RIVER INVESTORS held 625 BRK-B shares at 2026-06-30 per its 13F-HR filed 2026-08-03.

the latest 13F is the newest step

  1. period ended2026-06-30
    13F 625 shares
    Change vs previous 13F -200 shares

    0.12% of the 13F portfolio, value $312,744.

    13F-HR 0001384484-26-000006 filed by MAD RIVER INVESTORS
    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 825 shares
    Change vs previous 13F -300 shares

    0.14% of the 13F portfolio, value $395,340.

    13F-HR 0001384484-26-000004 filed by MAD RIVER INVESTORS
    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 1,125 shares
    Change vs previous 13F -50 shares

    0.26% of the 13F portfolio, value $565,482.

    13F-HR 0001384484-26-000002 filed by MAD RIVER INVESTORS
    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 1,175 shares
    Change vs previous 13F 0 shares

    0.25% of the 13F portfolio, value $590,720.

    13F-HR 0001384484-25-000009 filed by MAD RIVER INVESTORS
    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 1,175 shares
    Change vs previous 13F -725 shares

    0.26% of the 13F portfolio, value $570,780.

    13F-HR 0001384484-25-000007 filed by MAD RIVER INVESTORS
    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 1,900 shares
    Change vs previous 13F -4,825 shares

    0.43% of the 13F portfolio, value $1,011,902.

    13F-HR 0001384484-25-000005 filed by MAD RIVER INVESTORS
    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 6,725 shares
    Change vs previous 13F -500 shares

    1.42% of the 13F portfolio, value $3,048,308.

    13F-HR 0001384484-25-000002 filed by MAD RIVER INVESTORS
    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 7,225 shares
    Change vs previous 13F not available

    1.84% of the 13F portfolio, value $3,325,379.

    13F-HR 0001384484-24-000009 filed by MAD RIVER INVESTORS
    Filed (acceptance time not in the bulk data set), ingested

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