Insider transactions

Frank M Semple

CIK 1270065 · Chairman, President & CEO · last filed 2026-08-18

"Disclosed insider exposure" sums this person's most-recently-reported share counts across each company they're an insider in, multiplied by the current underlying price. It is not net worth — it misses retail holdings, private investments, real estate, index funds, and any company where the person isn't an SEC-reporting insider. For informational purposes only.

Loading insider history…
Disclosed Exposure
$30.12M
Companies
7
Total Filings
146
Lifetime Open-Market Net
-$7.13M

Charts

Trading activity, where the exposure sits, and each trade against the stock price.

MPLX price and trades

Daily close with each Form 4 filing on this company marked: green = open-market buy, red = open-market sale, purple = grants, exercises, gifts and other non-market transactions. Marker size scales with the dollar value.

Shares held

Shares owned after each reported transaction on this company (direct holdings as reported).

Open-market buying and selling

by month

Dollar value of open-market purchases (code P, up) and sales (code S, down) across all companies, by filing month. Grants, exercises and gifts are excluded.

Exposure by company

latest
OfficerDirector10% owner* stale (no filing in 3 yrs)

Most recently reported shares × current price. Faded bars (*) have had no filing in 3 years, so the person may no longer hold them. Click a bar to chart that company.

Filer Profile

Reported Address
539 SOUTH MAIN STREET
FINDLAY, OH 45840
Related Filers
Marathon Petroleum Corp — 29 joint filings, latest 2026-05-04
Profile details as reported on the filer's SEC submissions — for individual insiders the address is often in care of the issuer. Related filers are identified from jointly filed SEC submissions and shared reported addresses. View filings on SEC EDGAR.

Holdings By Company

Latest on-record share count from this person's most recent non-derivative Form 4 transaction in each company. Disclosed exposure = shares × current underlying price.
Symbol Role Shares Price Disclosed Exposure Lifetime OM Net Filings Latest Filed
MPLX Director 396,812 $58.16 $23.08M -$7.33M 85 2026-08-18
MPC Director 14,719 $478.07 $7.04M $0 27 2026-05-04
Hyliion Holdings Corp. (HYLN.WS) Delisted Director 40,000 — — $0 1 2020-10-05
ANDEAVOR LOGISTICS LP (ANDX) Delisted Director 2,359 — — $0 6 2019-07-03
Hyliion Holdings Corp. (SHLL.U) Delisted Director — — — $0 1 2019-03-06
MARKWEST ENERGY PARTNERS L P (MWE) Delisted Chairman, President & CEO 363,069 — — $204.0K 21 2015-02-03
MARKWEST HYDROCARBON INC (MWP) Delisted President, CEO 40,556 — — $0 2 2008-01-09

Recent Filings · Page 4 of 15

146 filings
Insider activity across all companies, newest first. Form 4 rows are post-trade confirmations (buys, sells, grants, exercises). Notice (144) rows are pre-trade notices of intent to sell restricted or control stock under Rule 144 — they may not all execute. Compare adjacent dates to see which notices became actual sales.
Filed Symbol Action Net Shares Net $ Link
2023-10-04 MPLX Grant (A) +1,014 $0 EDGAR
2023-08-16 MPLX Grant (A) +867 $0 EDGAR
2023-07-05 MPC Grant (A) +334 $0 EDGAR
2023-07-05 MPLX Grant (A) +937 $0 EDGAR
2023-05-17 MPLX Grant (A) +852 $0 EDGAR
2023-04-05 MPC Grant (A) +290 $0 EDGAR
2023-04-05 MPLX Grant (A) +916 $0 EDGAR
2023-02-16 MPLX Grant (A) +796 $0 EDGAR
2023-01-05 MPC Grant (A) +354 $0 EDGAR
2023-01-05 MPLX Grant (A) +978 $0 EDGAR
Showing 31–40 of 146
Page 4 of 15
Form 4 codes: P = open-market purchase · S = open-market sale · A = grant/award · M = option exercise · F = tax withholding at vest · G = bona-fide gift · D = disposition to issuer · J = other (see filing footnote). Only P / S codes carry directional signal.
Notice (144 / 144/A): Form 144 is a notice of intent to sell restricted/control stock under Rule 144, filed before the sale; 144/A is an amendment. Many notices are pre-scheduled under Rule 10b5-1 plans. A Form 4 with code S typically follows within a few days when the planned sale executes; missing follow-up Form 4s suggest the notice was cancelled or modified.