Marathon Petroleum Corporation
MX ˙ BMV ˙ US56585A1025
SecurityMX:MPC / Marathon Petroleum Corporation
InstitutionHorizon Investments, LLC
Latest Disclosed Ownership9,403 shares
Latest Disclosed Value $ 2,296,025
Horizon Investments, LLC reports 14.07% decrease in ownership of MPC / Marathon Petroleum Corporation

On May 14, 2026 - Horizon Investments, LLC filed a 13F-HR form disclosing ownership of 9,403 shares of Marathon Petroleum Corporation (MX:MPC) valued at $2,296,025 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 2, 2026 disclosing 10,943 shares of Marathon Petroleum Corporation. This represents a change in shares of -14.07% during the quarter.

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.

Upgrade to unlock premium data and export to Excel .

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)
2026-05-14 2026-03-31 13F MARATHON PETE CORP COM COM 56585A102 9,403 -1,540 -14.07 2,296 29.06 0.0219
2026-02-02 2025-12-31 13F MARATHON PETE CORP COM COM 56585A102 10,943 3,413 45.33 1,780 22.61 0.0225
2025-11-14 2025-09-30 13F MARATHON PETE CORP COM COM 56585A102 7,530 1,877 33.20 1,451 54.53 0.0191
2025-08-14 2025-06-30 13F MARATHON PETE CORP COM COM 56585A102 5,653 -3,560 -38.64 939 -30.03 0.0149
2025-05-13 2025-03-31 13F MARATHON PETE CORP COM COM 56585A102 9,213 -95 -1.02 1,342 3.39 0.0400
2025-02-10 2024-12-31 13F MARATHON PETE CORP COM COM 56585A102 9,308 91 0.99 1,298 -13.52 0.0373
2024-11-13 2024-09-30 13F MARATHON PETE CORP COM COM 56585A102 9,217 -661 -6.69 1,502 -12.38 0.0398
2024-08-09 2024-06-30 13F MARATHON PETE CORP COM COM 56585A102 9,878 -358 -3.50 1,714 -16.52 0.0474
2024-05-15 2024-03-31 13F MARATHON PETE CORP COM COM 56585A102 10,236 3,895 61.43 2,053 118.30 0.0539
2024-02-14 2023-12-31 13F MARATHON PETE CORP COM COM 56585A102 6,341 584 10.14 941 7.92 0.0262
2023-11-14 2023-09-30 13F MARATHON PETE CORP COM COM 56585A102 5,757 -440 -7.10 871 20.64 0.0265
2023-08-14 2023-06-30 13F MARATHON PETE CORP COM COM 56585A102 6,197 -1,795 -22.46 723 -32.96 0.0208
2023-05-15 2023-03-31 13F MARATHON PETE CORP COM COM 56585A102 7,992 -8,845 -52.53 1,078 107,600.00 0.0319
2023-02-14 2022-12-31 13F MARATHON PETE CORP COM COM 56585A102 16,837 2,926 21.03 2 -99.93 0.0552
2022-11-14 2022-09-30 13F MARATHON PETE CORP COM COM 56585A102 13,911 8,834 174.00 1,382 231.41 0.0425
2022-08-12 2022-06-30 13F MARATHON PETE CORP COM COM 56585A102 5,077 -788 -13.44 417 -16.77 0.0132
2022-05-16 2022-03-31 13F MARATHON PETE CORP COM COM 56585A102 5,865 1,071 22.34 501 63.19 0.0142
2022-02-15 2021-12-31 13F MARATHON PETE CORP COM COM 56585A102 4,794 325 7.27 307 11.23 0.0091
2021-11-15 2021-09-30 13F MARATHON PETE CORP COM COM 56585A102 4,469 -185 -3.98 276 -1.78 0.0072
2021-08-13 2021-06-30 13F MARATHON PETE CORP COM COM 56585A102 4,654 504 12.14 281 26.58 0.0084
2021-05-14 2021-03-31 13F MARATHON PETE CORP COM COM 56585A102 4,150 4,150 222 0.0082
2020-11-16 2020-09-30 13F MARATHON PETE CORP COM COM 56585A102 0 -8,806 -100.00 0 -100.00
2020-08-13 2020-06-30 13F MARATHON PETE CORP COM COM 56585A102 8,806 27 0.31 329 58.94 0.0081
2020-05-15 2020-03-31 13F MARATHON PETE CORP COM COM 56585A102 8,779 1,309 17.52 207 -54.00 0.0101
2020-02-14 2019-12-31 13F MARATHON PETE CORP COM COM 56585A102 7,470 3,680 97.10 450 95.65 0.0197
2019-11-14 2019-09-30 13F MARATHON PETE CORP COM COM 56585A102 3,790 -665 -14.93 230 -7.63 0.0093
2019-08-14 2019-06-30 13F MARATHON PETE CORP COM COM 56585A102 4,455 -49,106 -91.68 249 -92.23 0.0069
2019-05-16 2019-03-31 13F MARATHON PETE CORP COM COM 56585A102 53,561 53,561 3,206 0.1143
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.