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WILLIAM JOHN SEMPOLINSKI: MPLX position timeline

Available 13F reports, 13D and 13G stakes and each Form 3, 4 and 5 line of WILLIAM JOHN SEMPOLINSKI on MPLX, newest first. How the timeline and the estimate are built.

WILLIAM JOHN SEMPOLINSKI held 5,301 MPLX 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 5,301 shares
    Change vs previous 13F -238 shares

    0.12% of the 13F portfolio, value $298,605.

    13F-HR 0001951757-26-001260 filed by WILLIAM JOHN SEMPOLINSKI
    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 5,539 shares
    Change vs previous 13F +700 shares

    0.16% of the 13F portfolio, value $316,111.

    13F-HR 0001951757-26-001607 filed by WILLIAM JOHN SEMPOLINSKI
    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 4,839 shares
    Change vs previous 13F not available

    0.13% of the 13F portfolio, value $258,257.

    13F-HR 0001951757-26-001606 filed by WILLIAM JOHN SEMPOLINSKI
    Filed (acceptance time not in the bulk data set), ingested

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