Marathon Petroleum Corporation
US ˙ NYSE ˙ US56585A1025

SecurityMPC / Marathon Petroleum Corporation
InstitutionKeystone Financial Group
Latest Disclosed Ownership8,761 shares
Latest Disclosed Value $ 2,139,379
Keystone Financial Group reports 0.10% increase in ownership of MPC / Marathon Petroleum Corporation

On May 13, 2026 - Keystone Financial Group filed a 13F-HR form disclosing ownership of 8,761 shares of Marathon Petroleum Corporation (US:MPC) valued at $2,139,261 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 6, 2026 disclosing 8,752 shares of Marathon Petroleum Corporation. This represents a change in shares of 0.10% during the quarter. The current value of the position is $2,341,027 USD.

Institutional Ownership: 13F and NPORT Filings

The Security and Class in the table below are shown exactly as filed by the investor. We do our best to track continuity of investments through acquisitions, and this will be reflected in the table as changes in names. In addition to descriptive data, performance of the investment is shown over time. To calculate quarterly performance, we first calculate cost basis of the shares purchased during the quarter, then use that to calculate gross profit. Quarterly return is Gross Profit / Starting Portfolio value.

Note that cost basis is calculated and stored in thousands, so small quarterly changes in shares frequently result in a cost basis of zero.

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Disclosed Equity Positions (from 13F/NPORT Filings)
File
Date		 Effective
Date		Form Security Class ID Avg Price
Paid (Est)		 Reported
Shares		 ΔShares ΔShares
(%)		 Reported
Value
(x1000)		 ΔValue
(%)		 Alloc
(%)		 ΔAlloc ΔAlloc (%) Cost Basis
(x1000)		 Unrealized
Gain/Loss
(x1000)
2026-05-13 2026-03-31 13F MARATHON PETROLEUM Equtities 56585A102 8,761 9 0.10 2,139 50.32 0.1439
2026-02-06 2025-12-31 13F MARATHON PETROLEUM Equities 56585A102 8,752 -40 -0.45 1,423 -16.00 0.1053
2025-11-17 2025-09-30 13F/A-1 MARATHON PETROLEUM Common Stock 56585A102 8,792 81 0.93 1,695 17.15 0.1295
2025-11-14 2025-09-30 13F MARATHON PETROLEUM Common Stock 56585A102 8,711 0 1,447 0.1150
2025-08-13 2025-06-30 13F MARATHON PETROLEUM Common Stock 56585A102 8,711 432 5.22 1,447 19.90 0.1305
2025-05-13 2025-03-31 13F MARATHON PETROLEUM Common Stock 56585A102 8,279 -31 -0.37 1,206 4.06 0.1226
2025-02-13 2024-12-31 13F MARATHON PETROLEUM Common Stock 56585A102 8,310 18 0.22 1,159 -14.15 0.1140
2025-02-19 2024-09-30 13F/A-3 MARATHON PETROLEUM Common Stock 56585A102 8,292 382 4.83 1,351 -1.60 0.1729
2025-02-18 2024-09-30 13F/A-2 MARATHON PETROLEUM Common Stock 56585A102 25,288 17,378 1,346 0.1751
2024-11-12 2024-09-30 13F MARATHON PETROLEUM Common Stock 56585A102 8,292 382 1,351 0.4460
2024-07-31 2024-06-30 13F MARATHON PETROLEUM Common Stock 56585A102 7,910 -76 -0.95 1,372 -14.73 0.4915
2024-05-08 2024-03-31 13F MARATHON PETROLEUM Common Stock 56585A102 7,986 3,413 74.63 1,609 137.32 0.2344
2024-02-14 2023-12-31 13F/A-1 MARATHON PETROLEUM Common Stock 56585A102 4,573 920 25.18 678 22.83 0.1180
2024-02-09 2023-12-31 13F MARATHON PETROLEUM Common Stock 56585A102 4,573 920 678 0.1180
2023-11-06 2023-09-30 13F MARATHON PETROLEUM Common Stock 56585A102 3,653 -194 -5.04 553 23.21 0.0926
2023-08-07 2023-06-30 13F MARATHON PETROLEUM Common Stock 56585A102 3,847 915 31.21 449 31.38 0.0763
2023-02-07 2022-12-31 13F MARATHON PETROLEUM Common Stock 56585A102 2,932 -542 -15.60 341 -1.16 0.0674
2022-11-10 2022-09-30 13F MARATHON PETROLEUM Common Stock 56585A102 3,474 -963 -21.70 345 -5.48 0.0700
2022-08-05 2022-06-30 13F MARATHON PETROLEUM Common Stock 56585A102 4,437 -45 -1.00 365 -4.70 0.0723
2022-05-13 2022-03-31 13F MARATHON PETROLEUM Common Stock 56585A102 4,482 -954 -17.55 383 10.06 0.0650
2022-02-11 2021-12-31 13F MARATHON PETROLEUM Common Stock 56585A102 5,436 2 0.04 348 3.57 0.0571
2021-11-12 2021-09-30 13F MARATHON PETROLEUM Common Stock 56585A102 5,434 3 0.06 336 2.44 0.0608
2021-08-13 2021-06-30 13F MARATHON PETROLEUM Common Stock 56585A102 5,431 524 10.68 328 25.19 0.0594
2021-05-11 2021-03-31 13F MARATHON PETROLEUM Common Stock 56585A102 4,907 1,144 30.40 262 15.42 0.0510
2020-05-05 2020-03-31 13F MARATHON PETROLEUM Common Stock 56585A102 3,763 0 0.00 227 0.00 0.0610
2020-02-06 2019-12-31 13F MARATHON PETROLEUM Common Stock 56585A102 3,763 0 0.00 227 -0.87 0.0610
2019-11-07 2019-09-30 13F MARATHON PETROLEUM Common Stock 56585A102 3,763 3,763 229 0.0704
2019-08-07 2019-06-30 13F MARATHON PETROLEUM Common Stock 56585A102 0 -3,802 -100.00 0 -100.00
2019-05-07 2019-03-31 13F MARATHON PETROLEUM Common Stock 56585A102 3,802 3,802 228 0.0811
Legend
Shares
The total number of shares held by the institution at the end of the reporting period (the effective date). This is provided in the filing.
Value
The total value of the shares as of the effective date. This is provided in the filing.
Avg. Share Price
The weighted average share price of the shares held by the institution. We use FIFO accounting to determine this price
Class
This is the security class as indicated by the filer. There are a variety of values for this field. Common values include "EC" = equity common, "EP" - equity preferred
Allocation (%)
The percent of the institution's portfolio that this position represents. This is provided in NPORT filings. For 13F filings, we calculate it.
Change in Allocation
The change in allocation from the prior reporting period. This is calculated as current allocation - prior allocation.
Change in Allocation (%)
The percent change in allocation from the prior reporting period. This is calculated as (current allocation - prior allocation) / prior allocation.
Cost Basis
The total cost of the shares held. This is calculated as reported shares * avg. share price
Unrealized Gain/Loss
This is the market value of the position as of the effective date minus the cost basis.