Marathon Petroleum Corporation
MX ˙ BMV ˙ US56585A1025
SecurityMX:MPC / Marathon Petroleum Corporation
InstitutionChoate Investment Advisors
Latest Disclosed Ownership12,870 shares
Latest Disclosed Value $ 3,142,597
Choate Investment Advisors reports 8.64% increase in ownership of MPC / Marathon Petroleum Corporation

On May 13, 2026 - Choate Investment Advisors filed a 13F-HR form disclosing ownership of 12,870 shares of Marathon Petroleum Corporation (MX:MPC) valued at $3,142,597 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 9, 2026 disclosing 11,846 shares of Marathon Petroleum Corporation. This represents a change in shares of 8.64% 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)
2026-05-13 2026-03-31 13F MARATHON PETE COM 56585A102 12,870 1,024 8.64 3,143 63.14 0.0615
2026-02-09 2025-12-31 13F MARATHON PETE COM 56585A102 11,846 0 0.00 1,927 -15.64 0.0378
2025-11-10 2025-09-30 13F MARATHON PETE COM 56585A102 11,846 201 1.73 2,283 18.05 0.0472
2025-08-12 2025-06-30 13F MARATHON PETE COM 56585A102 11,645 -27 -0.23 1,934 13.76 0.0419
2025-05-14 2025-03-31 13F MARATHON PETE COM 56585A102 11,672 20 0.17 1,700 4.62 0.0423
2025-02-10 2024-12-31 13F MARATHON PETE COM 56585A102 11,652 398 3.54 1,625 -11.35 0.0391
2024-11-13 2024-09-30 13F MARATHON PETE COM 56585A102 11,254 255 2.32 1,833 -3.93 0.0467
2024-08-08 2024-06-30 13F MARATHON PETE COM 56585A102 10,999 -4 -0.04 1,908 -13.94 0.0500
2024-05-07 2024-03-31 13F MARATHON PETE COM 56585A102 11,003 -410 -3.59 2,217 30.95 0.0597
2024-02-14 2023-12-31 13F MARATHON PETE COM 56585A102 11,413 -434 -3.66 1,693 -5.52 0.0524
2023-10-30 2023-09-30 13F MARATHON PETE COM 56585A102 11,847 571 5.06 1,793 36.38 0.0703
2023-08-01 2023-06-30 13F MARATHON PETE COM 56585A102 11,276 821 7.85 1,315 -6.74 0.0550
2023-05-15 2023-03-31 13F MARATHON PETE COM 56585A102 10,455 0 0.00 1,410 15.87 0.0681
2023-02-14 2022-12-31 13F MARATHON PETE COM 56585A102 10,455 -185 -1.74 1,217 15.04 0.0734
2022-11-14 2022-09-30 13F MARATHON PETE COM 56585A102 10,640 0 0.00 1,057 20.80 0.0696
2022-08-11 2022-06-30 13F MARATHON PETE COM 56585A102 10,640 0 0.00 875 -3.85 0.0531
2022-04-29 2022-03-31 13F MARATHON PETE COM 56585A102 10,640 0 0.00 910 33.63 0.0483
2022-02-07 2021-12-31 13F MARATHON PETE COM 56585A102 10,640 240 2.31 681 5.91 0.0398
2021-11-04 2021-09-30 13F MARATHON PETE COM 56585A102 10,400 -12 -0.12 643 2.23 0.0410
2021-07-30 2021-06-30 13F MARATHON PETE COM 56585A102 10,412 -12 -0.12 629 12.72 0.0381
2021-05-07 2021-03-31 13F MARATHON PETE COM 56585A102 10,424 -128 -1.21 558 27.98 0.0345
2021-02-08 2020-12-31 13F MARATHON PETE COM 56585A102 10,552 152 1.46 436 42.95 0.0265
2020-10-26 2020-09-30 13F MARATHON PETE COM 56585A102 10,400 -164 -1.55 305 -22.78 0.0198
2020-07-23 2020-06-30 13F MARATHON PETE COM 56585A102 10,564 0 0.00 395 58.00 0.0287
2020-05-07 2020-03-31 13F MARATHON PETE COM 56585A102 10,564 0 0.00 250 -60.69 0.0199
2020-01-28 2019-12-31 13F MARATHON PETE COM 56585A102 10,564 0 0.00 636 -0.93 0.0387
2019-11-12 2019-09-30 13F MARATHON PETE COM 56585A102 10,564 -15 -0.14 642 8.63 0.0397
2019-08-14 2019-06-30 13F MARATHON PETE COM 56585A102 10,579 0 0.00 591 -6.64 0.0354
2019-04-29 2019-03-31 13F MARATHON PETE COM 56585A102 10,579 0 0.00 633 1.44 0.0374
2019-02-14 2018-12-31 13F MARATHON PETE COM 56585A102 10,579 0 0.00 624 -26.24 0.0402
2018-11-14 2018-09-30 13F MARATHON PETE COM 56585A102 10,579 -31 -0.29 846 13.71 0.0467
2018-07-30 2018-06-30 13F MARATHON PETE COM 56585A102 10,610 0 0.00 744 -4.00 0.0432
2018-05-04 2018-03-31 13F MARATHON PETROLEUM COM 56585A102 10,610 0 0.00 776 10.71 0.0415
2018-02-14 2017-12-31 13F MARATHON PETROLEUM COM 56585A102 10,610 -24 -0.23 700 17.45 0.0358
2017-11-14 2017-09-30 13F MARATHON PETROLEUM COM 56585A102 10,634 24 0.23 596 7.39 0.0322
2017-08-11 2017-06-30 13F MARATHON PETROLEUM COM 56585A102 10,610 -15 -0.14 555 3.54 0.0314
2017-05-11 2017-03-31 13F MARATHON PETROLEUM COM 56585A102 10,625 -584 -5.21 537 -4.96 0.0314
2017-02-13 2016-12-31 13F MARATHON PETROLEUM COM 56585A102 11,209 -135 -1.19 564 22.61 0.0357
2016-11-15 2016-09-30 13F MARATHON PETROLEUM COM 56585A102 11,344 20 0.18 460 7.23 0.0301
2016-08-11 2016-06-30 13F MARATHON PETROLEUM COM 56585A102 11,324 -6,180 -35.31 430 -34.00 0.0298
2016-05-04 2016-03-31 13F MARATHON PETROLEUM COM 56585A102 17,504 8,703 98.89 651 -18.14 0.0450
2016-03-30 2015-12-31 13F/A-1 MARATHON PETROLEUM COM 56585A102 8,801 -9,103 -50.84 794 -4.22 0.0578
2016-02-16 2015-12-31 13F MARATHON PETROLEUM COM 56585A102 17,904 829
2015-11-12 2015-09-30 13F MARATHON PETROLEUM COM 56585A102 17,904 0 0.00 829 -11.43 0.0566
2015-08-13 2015-06-30 13F MARATHON PETROLEUM COM 56585A102 17,904 8,941 99.75 937 2.07 0.0541
2015-05-14 2015-03-31 13F MARATHON PETROLEUM COM 56585A102 8,963 162 1.84 918 15.49 0.0520
2015-02-17 2014-12-31 13F MARATHON PETROLEUM COM 56585A102 8,801 11 0.13 794 6.72 0.0466
2014-11-13 2014-09-30 13F MARATHON PETROLEUM COM 56585A102 8,790 300 3.53 744 12.39 0.0450
2014-08-14 2014-06-30 13F/A-1 MARATHON PETROLEUM COM 56585A102 8,490 -560 -6.19 663 -15.88 0.0389
2014-08-14 2014-06-30 13F MARATHON PETROLEUM COM 56585A102 8,490 663
2014-05-15 2014-03-31 13F MARATHON PETROLEUM COM 56585A102 9,050 200 2.26 788 -2.96 0.0489
2014-02-05 2013-12-31 13F/A-1 MARATHON PETROLEUM COM 56585A102 8,850 0 0.00 812 -99.86 0.0531
2014-02-04 2013-12-31 13F MARATHON PETROLEUM COM 56585A102 8,850 569,232
2013-11-05 2013-09-30 13F MARATHON PETROLEUM COM 56585A102 8,850 0 0.00 569,232 -9.48 0.0421
2013-08-12 2013-06-30 13F MARATHON PETROLEUM COM 56585A102 8,850 8,850 628,881 0.0504
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.