Marathon Petroleum Corporation
MX ˙ BMV ˙ US56585A1025
SecurityMX:MPC / Marathon Petroleum Corporation
InstitutionBoston Partners
Latest Disclosed Ownership5,649,204 shares
Latest Disclosed Value $ 1,378,883,125
Boston Partners reports 7.69% decrease in ownership of MPC / Marathon Petroleum Corporation

On May 11, 2026 - Boston Partners filed a 13F-HR form disclosing ownership of 5,649,204 shares of Marathon Petroleum Corporation (MX:MPC) valued at $1,378,883,125 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 13, 2026 disclosing 6,119,715 shares of Marathon Petroleum Corporation. This represents a change in shares of -7.69% 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.

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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)
2026-05-11 2026-03-31 13F MARATHON PETE COM 56585A102 5,649,204 -470,511 -7.69 1,378,883 38.18 0.6172
2026-02-13 2025-12-31 13F MARATHON PETE COM 56585A102 6,119,715 -185,713 -2.95 997,916 -17.83 1.0332
2025-11-13 2025-09-30 13F MARATHON PETE COM 56585A102 6,305,428 141,691 2.30 1,214,522 18.56 1.2470
2025-08-12 2025-06-30 13F/A-1 MARATHON PETE COM 56585A102 6,163,737 715,223 13.13 1,024,395 29.46 1.1376
2025-08-07 2025-06-30 13F MARATHON PETE COM 56585A102 6,155,996 707,482 1,023,110 0.4698
2025-05-13 2025-03-31 13F MARATHON PETE COM 56585A102 5,448,514 2,011,810 58.54 791,274 64.68 0.9569
2025-02-11 2024-12-31 13F MARATHON PETE COM 56585A102 3,436,704 935,042 37.38 480,501 18.18 0.5844
2024-11-12 2024-09-30 13F MARATHON PETE COM 56585A102 2,501,662 -60,675 -2.37 406,595 -8.33 0.4799
2024-08-14 2024-06-30 13F MARATHON PETE COM 56585A102 2,562,337 -210,713 -7.60 443,537 -20.57 0.5510
2024-05-28 2024-03-31 13F/A-1 MARATHON PETE COM 56585A102 2,773,050 8,476 0.31 558,390 35.99 0.6651
2024-05-13 2024-03-31 13F MARATHON PETE COM 56585A102 2,773,050 8,476 558,390 0.2763
2024-02-07 2023-12-31 13F MARATHON PETE COM 56585A102 2,764,574 -1,732,203 -38.52 410,616 -39.63 0.5438
2023-11-08 2023-09-30 13F MARATHON PETE COM 56585A102 4,496,777 -686,047 -13.24 680,124 11.64 0.9416
2023-08-10 2023-06-30 13F MARATHON PETE COM 56585A102 5,182,824 -1,226,649 -19.14 609,196 -29.25 0.8200
2023-05-09 2023-03-31 13F MARATHON PETE COM 56585A102 6,409,473 -475,526 -6.91 861,049 7.23 1.1838
2023-02-08 2022-12-31 13F MARATHON PETE COM 56585A102 6,884,999 -1,074,421 -13.50 802,972 1.09 1.0862
2022-11-09 2022-09-30 13F MARATHON PETE COM 56585A102 7,959,420 -827,427 -9.42 794,323 9.65 1.1625
2022-08-10 2022-06-30 13F MARATHON PETE COM 56585A102 8,786,847 -1,858,496 -17.46 724,406 -20.42 1.0124
2022-05-10 2022-03-31 13F MARATHON PETE COM 56585A102 10,645,343 -1,286,391 -10.78 910,251 19.06 1.1027
2022-02-04 2021-12-31 13F MARATHON PETE COM 56585A102 11,931,734 -369,278 -3.00 764,506 0.52 0.9209
2021-11-05 2021-09-30 13F MARATHON PETE COM 56585A102 12,301,012 124,088 1.02 760,536 3.41 0.9635
2021-08-12 2021-06-30 13F MARATHON PETE COM 56585A102 12,176,924 6,145 0.05 735,440 12.98 0.9379
2021-05-10 2021-03-31 13F MARATHON PETE COM 56585A102 12,170,779 1,855,636 17.99 650,960 52.58 0.8730
2021-02-10 2020-12-31 13F/A-1 MARATHON PETE COM 56585A102 10,315,143 -1,113,645 -9.74 426,635 27.23 0.6635
2021-02-04 2020-12-31 13F MARATHON PETE COM 56585A102 10,315,143 -1,113,645 426,635 255,955.6415
2020-11-13 2020-09-30 13F/A-1 MARATHON PETE COM 56585A102 11,428,788 -485,130 -4.07 335,321 -24.68 0.6106
2020-11-09 2020-09-30 13F MARATHON PETE COM 56585A102 11,913,918 0 445,193 326,824.6944
2020-08-12 2020-06-30 13F MARATHON PETE COM 56585A102 11,913,918 45,194 0.38 445,193 58.94 0.8177
2020-05-13 2020-03-31 13F MARATHON PETE COM 56585A102 11,868,724 -5,133,037 -30.19 280,093 -72.66 0.5562
2020-02-06 2019-12-31 13F/A-1 MARATHON PETE COM 56585A102 17,001,761 4,194,733 32.75 1,024,564 31.60 1.3551
2020-02-05 2019-12-31 13F MARATHON PETE COM 56585A102 17,001,761 4,194,733 1,024,564 576,039.8051
2019-11-20 2019-09-30 13F/A-1 MARATHON PETE COM 56585A102 12,807,028 5,604,647 77.82 778,559 93.47 1.0543
2019-11-08 2019-09-30 13F MARATHON PETE COM 56585A102 7,314,795 112,414 410,546 0.5430
2019-08-26 2019-06-30 13F/A-1 MARATHON PETE COM 56585A102 7,202,381 4,914,767 214.84 402,410 193.91 0.5277
2019-08-09 2019-06-30 13F MARATHON PETE COM 56585A102 7,202,684 4,915,070 402,427
2019-05-13 2019-03-31 13F/A-1 MARATHON PETE COM 56585A102 2,287,614 -9,885,751 -81.21 136,914 -80.94 0.1814
2019-05-03 2019-03-31 13F MARATHON PETE COM 56585A102 2,287,614 -9,885,751 136,914
2019-02-07 2018-12-31 13F MARATHON PETE COM 56585A102 12,173,365 5,479,818 81.87 718,350 34.20 1.0322
2018-11-14 2018-09-30 13F MARATHON PETE COM 56585A102 6,693,547 -944,919 -12.37 535,282 -0.12 0.6220
2018-08-03 2018-06-30 13F MARATHON PETE COM 56585A102 7,638,466 -59,998 -0.78 535,914 -4.78 0.6423
2018-05-04 2018-03-31 13F MARATHON PETE COM 56585A102 7,698,464 -1,282,955 -14.28 562,835 -5.02 0.6786
2018-02-14 2017-12-31 13F/A-1 MARATHON PETE COM 56585A102 8,981,419 -73,452 -0.81 592,593 16.70 0.6981
2018-02-01 2017-12-31 13F MARATHON PETE COM 56585A102 8,981,419 -73,452 592,593
2017-11-02 2017-09-30 13F MARATHON PETE COM 56585A102 9,054,871 -74,404 -0.82 507,798 6.29 0.6275
2017-08-02 2017-06-30 13F MARATHON PETE COM 56585A102 9,129,275 -5,669,545 -38.31 477,735 -36.13 0.6075
2017-05-03 2017-03-31 13F MARATHON PETE COM 56585A102 14,798,820 267,469 1.84 747,933 2.22 0.9550
2017-02-06 2016-12-31 13F MARATHON PETE COM 56585A102 14,531,351 8,043,571 123.98 731,654 177.84 0.9620
2016-11-09 2016-09-30 13F MARATHON PETE COM 56585A102 6,487,780 -4,917,756 -43.12 263,339 -39.18 0.3682
2016-08-05 2016-06-30 13F MARATHON PETE COM 56585A102 11,405,536 4,155,419 57.32 432,954 60.62 0.6256
2016-05-12 2016-03-31 13F MARATHON PETE COM 56585A102 7,250,117 357,034 5.18 269,560 -24.56 0.3970
2016-02-08 2015-12-31 13F MARATHON PETE COM 56585A102 6,893,083 -1,178,175 -14.60 357,337 -4.44 0.5119
2015-11-10 2015-09-30 13F MARATHON PETE COM 56585A102 8,071,258 561,826 7.48 373,941 -4.81 0.5700
2015-08-10 2015-06-30 13F MARATHON PETE COM 56585A102 7,509,432 1,439,231 23.71 392,818 -36.80 0.5643
2015-05-05 2015-03-31 13F MARATHON PETE COM 56585A102 6,070,201 226,013 3.87 621,529 17.83 0.9253
2015-02-09 2014-12-31 13F MARATHON PETE COM 56585A102 5,844,188 923,105 18.76 527,497 26.60 0.7917
2014-11-12 2014-09-30 13F MARATHON PETE COM 56585A102 4,921,083 554,810 12.71 416,669 22.24 0.6762
2014-08-08 2014-06-30 13F MARATHON PETE COM 56585A102 4,366,273 3,540,051 428.46 340,875 374.00 0.5709
2014-05-07 2014-03-31 13F MARATHON PETE COM 56585A102 826,222 343,227 71.06 71,915 62.32 0.1312
2014-02-06 2013-12-31 13F MARATHON PETE COM 56585A102 482,995 110,791 29.77 44,305 85.07 0.0908
2013-11-12 2013-09-30 13F MARATHON PETE COM 56585A102 372,204 -17,179 -4.41 23,940 -13.48 0.0577
2013-08-01 2013-06-30 13F MARATHON PETE COM 56585A102 389,383 389,383 27,669 0.0762
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.