Marathon Petroleum Corporation
US ˙ NYSE ˙ US56585A1025

SecurityMPC / Marathon Petroleum Corporation
InstitutionCastleark Management Llc
Latest Disclosed Ownership22,400 shares
Latest Disclosed Value $ 5,469,632
Castleark Management Llc ownership in MPC / Marathon Petroleum Corporation

On May 15, 2026 - Castleark Management Llc filed a 13F-HR form disclosing ownership of 22,400 shares of Marathon Petroleum Corporation (US:MPC) valued at $5,469,632 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 12, 2026 disclosing 0 shares of Marathon Petroleum Corporation. The current value of the position is $5,985,504 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)
2026-05-15 2026-03-31 13F MARATHON PETE COM 56585A102 22,400 22,400 5,470 0.1810
2026-02-12 2025-12-31 13F MARATHON PETE COM 56585A102 0 -46,258 -100.00 0 -100.00
2025-11-17 2025-09-30 13F MARATHON PETE COM 56585A102 46,258 43,920 1,878.53 8,916 2,197.68 0.2500
2025-08-18 2025-06-30 13F MARATHON PETE COM 56585A102 2,338 0 0.00 388 14.12 0.0117
2025-05-15 2025-03-31 13F MARATHON PETE COM 56585A102 2,338 -96,051 -97.62 341 -97.52 0.0118
2025-02-18 2024-12-31 13F MARATHON PETE COM 56585A102 98,389 87,150 775.42 13,725 650.00 0.4787
2024-11-15 2024-09-30 13F MARATHON PETE COM 56585A102 11,239 -6,040 -34.96 1,831 -38.94 0.0746
2024-08-14 2024-06-30 13F MARATHON PETE COM 56585A102 17,279 -2,460 -12.46 2,998 -24.64 0.1224
2024-05-16 2024-03-31 13F MARATHON PETE COM 56585A102 19,739 3,200 19.35 3,977 62.13 0.1655
2024-02-15 2023-12-31 13F MARATHON PETE COM 56585A102 16,539 0 0.00 2,454 -2.00 0.1088
2023-11-15 2023-09-30 13F MARATHON PETE COM 56585A102 16,539 3,770 29.52 2,503 68.21 0.1275
2023-08-16 2023-06-30 13F MARATHON PETE COM 56585A102 12,769 -14,100 -52.48 1,489 -58.92 0.0674
2023-05-16 2023-03-31 13F MARATHON PETE COM 56585A102 26,869 0 0.00 3,623 15.83 0.1780
2023-02-10 2022-12-31 13F MARATHON PETE COM 56585A102 26,869 0 0.00 3,127 17.16 0.1634
2022-11-15 2022-09-30 13F MARATHON PETE COM 56585A102 26,869 -6,710 -19.98 2,669 -3.33 0.1485
2022-08-16 2022-06-30 13F MARATHON PETE COM 56585A102 33,579 0 0.00 2,761 -3.83 0.1478
2022-05-16 2022-03-31 13F MARATHON PETE COM 56585A102 33,579 -6,610 -16.45 2,871 11.63 0.1239
2022-02-16 2021-12-31 13F MARATHON PETE COM 56585A102 40,189 -6,750 -14.38 2,572 -11.34 0.0946
2021-11-12 2021-09-30 13F MARATHON PETE COM 56585A102 46,939 -10,315 -18.02 2,901 -16.13 0.1109
2021-08-17 2021-06-30 13F MARATHON PETE COM 56585A102 57,254 1,606 2.89 3,459 16.19 0.1162
2021-05-14 2021-03-31 13F MARATHON PETE COM 56585A102 55,648 -12,893 -18.81 2,977 5.01 0.1072
2021-02-17 2020-12-31 13F MARATHON PETE COM 56585A102 68,541 57,960 547.77 2,835 814.52 0.1061
2020-11-16 2020-09-30 13F MARATHON PETE COM 56585A102 10,581 -103,449 -90.72 310 -92.73 0.0121
2020-08-14 2020-06-30 13F MARATHON PETE COM 56585A102 114,030 86,110 308.42 4,262 546.74 0.1853
2020-05-13 2020-03-31 13F MARATHON PETE COM 56585A102 27,920 -79,570 -74.03 659 -89.82 0.0390
2020-02-14 2019-12-31 13F MARATHON PETE COM 56585A102 107,490 -29,610 -21.60 6,476 -22.25 0.2592
2019-11-15 2019-09-30 13F MARATHON PETE COM 56585A102 137,100 -463 -0.34 8,329 8.35 0.3398
2019-08-13 2019-06-30 13F MARATHON PETE COM 56585A102 137,563 -340 -0.25 7,687 -6.86 0.2949
2019-05-14 2019-03-31 13F MARATHON PETE COM 56585A102 137,903 73,315 113.51 8,253 116.56 0.3107
2019-02-12 2018-12-31 13F MARATHON PETE COM 56585A102 64,588 12,838 24.81 3,811 -7.90 0.1624
2018-11-14 2018-09-30 13F MARATHON PETE COM 56585A102 51,750 5,545 12.00 4,138 27.64 0.1189
2018-08-15 2018-06-30 13F MARATHON PETE COM 56585A102 46,205 -38,870 -45.69 3,242 -47.88 0.0998
2018-05-14 2018-03-31 13F MARATHON PETE COM 56585A102 85,075 32,800 62.75 6,220 80.34 0.1970
2018-02-15 2017-12-31 13F MARATHON PETE COM 56585A102 52,275 23,800 83.58 3,449 115.97 0.1035
2017-11-15 2017-09-30 13F MARATHON PETE COM 56585A102 28,475 -25,400 -47.15 1,597 -43.35 0.0501
2017-08-15 2017-06-30 13F MARATHON PETE COM 56585A102 53,875 -134,340 -71.38 2,819 -70.36 0.0921
2017-05-15 2017-03-31 13F MARATHON PETE COM 56585A102 188,215 42,870 29.50 9,512 29.98 0.2981
2017-02-15 2016-12-31 13F MARATHON PETE COM 56585A102 145,345 145,345 0.00 7,318 0.2334
2016-08-10 2016-06-30 13F MARATHON PETE COM 56585A102 0 -29,500 -100.00 0 -100.00
2016-05-17 2016-03-31 13F MARATHON PETE COM 56585A102 29,500 29,500 0.00 1,097 0.0343
2016-02-17 2015-12-31 13F MARATHON PETE COM 56585A102 0 0 0 0.0000
2015-11-17 2015-09-30 13F MARATHON PETE COM 56585A102 0 -190,200 -100.00 0 -100.00
2015-08-17 2015-06-30 13F MARATHON PETE COM 56585A102 190,200 170,300 855.78 9,949 388.17 0.2658
2015-05-15 2015-03-31 13F MARATHON PETE COM 56585A102 19,900 -71,400 -78.20 2,038 -75.27 0.0491
2015-02-10 2014-12-31 13F MARATHON PETE COM 56585A102 91,300 -14,900 -14.03 8,241 -10.85 0.2123
2014-11-17 2014-09-30 13F MARATHON PETE COM 56585A102 106,200 94,750 827.51 9,244 934.00 0.2628
2014-08-15 2014-06-30 13F MARATHON PETROLEUM COM 56585A102 11,450 -94,750 -89.22 894 -90.33 0.0246
2014-05-20 2014-03-31 13F MARATHON PETE COM 56585A102 106,200 46,400 77.59 9,244 117.56 0.2628
2013-09-26 2013-06-30 13F MARATHON PETE COM 56585A102 59,800 59,800 4,249 0.1410
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.