Marathon Petroleum Corporation
US ˙ NYSE ˙ US56585A1025

SecurityMPC / Marathon Petroleum Corporation
InstitutionNorthwestern Mutual Wealth Management Co
Latest Disclosed Ownership46,761 shares
Latest Disclosed Value $ 11,418,138
Northwestern Mutual Wealth Management Co reports 16.87% increase in ownership of MPC / Marathon Petroleum Corporation

On May 7, 2026 - Northwestern Mutual Wealth Management Co filed a 13F-HR form disclosing ownership of 46,761 shares of Marathon Petroleum Corporation (US:MPC) valued at $11,418,101 USD as of March 31, 2026. The entity filed a previous 13F-HR/A on February 10, 2026 disclosing 40,010 shares of Marathon Petroleum Corporation. This represents a change in shares of 16.87% during the quarter. The current value of the position is $12,251,850 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)
2026-05-07 2026-03-31 13F MARATHON PETE COM 56585A102 46,761 6,751 16.87 11,418 75.50 0.0070
2026-02-10 2025-12-31 13F/A-1 MARATHON PETE COM 56585A102 40,010 974 2.50 6,507 -13.52 0.0041
2026-02-05 2025-12-31 13F MARATHON PETE COM 56585A102 2,463 -36,573 842 0.0005
2025-11-14 2025-09-30 13F MARATHON PETE COM 56585A102 39,036 127 0.33 7,524 16.40 0.0050
2025-08-13 2025-06-30 13F MARATHON PETE COM 56585A102 38,909 420 1.09 6,463 15.27 0.0047
2025-05-14 2025-03-31 13F MARATHON PETE COM 56585A102 38,489 3,649 10.47 5,607 15.37 0.0046
2025-02-11 2024-12-31 13F MARATHON PETE COM 56585A102 34,840 -1,516 -4.17 4,860 -17.93 0.0041
2024-11-12 2024-09-30 13F MARATHON PETE COM 56585A102 36,356 -2,932 -7.46 5,923 -13.10 0.0053
2024-08-16 2024-06-30 13F MARATHON PETE COM 56585A102 39,288 1,432 3.78 6,816 -10.65 0.0067
2024-05-15 2024-03-31 13F MARATHON PETE COM 56585A102 37,856 -1,202 -3.08 7,628 31.64 0.0078
2024-02-13 2023-12-31 13F MARATHON PETE COM 56585A102 39,058 1,464 3.89 5,795 1.85 0.0065
2023-11-14 2023-09-30 13F MARATHON PETE COM 56585A102 37,594 -120 -0.32 5,689 29.38 0.0074
2023-08-14 2023-06-30 13F MARATHON PETE COM 56585A102 37,714 841 2.28 4,397 -11.55 0.0057
2023-05-15 2023-03-31 13F MARATHON PETE COM 56585A102 36,873 -3,475 -8.61 4,972 5.86 0.0069
2023-02-21 2022-12-31 13F MARATHON PETE COM 56585A102 40,348 -247 -0.61 4,696 16.47 0.0071
2022-11-14 2022-09-30 13F MARATHON PETE COM 56585A102 40,595 870 2.19 4,032 23.49 0.0070
2022-08-04 2022-06-30 13F MARATHON PETE COM 56585A102 39,725 1,961 5.19 3,265 1.15 0.0056
2022-05-09 2022-03-31 13F MARATHON PETE COM 56585A102 37,764 2,642 7.52 3,228 43.66 0.0052
2022-02-03 2021-12-31 13F MARATHON PETE COM 56585A102 35,122 -12,091 -25.61 2,247 -23.02 0.0037
2021-11-15 2021-09-30 13F MARATHON PETE COM 56585A102 47,213 3,866 8.92 2,919 11.45 0.0053
2021-08-13 2021-06-30 13F MARATHON PETE COM 56585A102 43,347 -2,930 -6.33 2,619 5.82 0.0050
2021-05-14 2021-03-31 13F MARATHON PETE COM 56585A102 46,277 -3,475 -6.98 2,475 20.26 0.0053
2021-02-12 2020-12-31 13F MARATHON PETE COM 56585A102 49,752 -1,799 -3.49 2,058 36.02 0.0048
2020-11-13 2020-09-30 13F MARATHON PETE COM 56585A102 51,551 -34,762 -40.27 1,513 -53.11 0.0041
2020-08-14 2020-06-30 13F MARATHON PETE COM 56585A102 86,313 -8,151 -8.63 3,227 44.64 0.0100
2020-05-08 2020-03-31 13F MARATHON PETE COM 56585A102 94,464 8,954 10.47 2,231 -56.69 0.0086
2020-02-13 2019-12-31 13F MARATHON PETE COM 56585A102 85,510 -4,375 -4.87 5,151 -5.68 0.0176
2019-11-12 2019-09-30 13F MARATHON PETE COM 56585A102 89,885 41,542 85.93 5,461 102.18 0.0207
2019-08-12 2019-06-30 13F MARATHON PETE COM 56585A102 48,343 4,397 10.01 2,701 2.70 0.0109
2019-05-10 2019-03-31 13F MARATHON PETE COM 56585A102 43,946 8,875 25.31 2,630 27.11 0.0115
2019-02-12 2018-12-31 13F MARATHON PETE COM 56585A102 35,071 7,563 27.49 2,069 -5.95 0.0104
2018-11-01 2018-09-30 13F MARATHON PETE COM 56585A102 27,508 1,951 7.63 2,200 22.63 0.0111
2018-08-10 2018-06-30 13F MARATHON PETE COM 56585A102 25,557 3,850 17.74 1,794 13.04 0.0100
2018-05-14 2018-03-31 13F MARATHON PETE COM 56585A102 21,707 31 0.14 1,587 10.98 0.0096
2018-01-31 2017-12-31 13F MARATHON PETE COM 56585A102 21,676 -54 -0.25 1,430 17.41 0.0091
2017-11-07 2017-09-30 13F MARATHON PETE COM 56585A102 21,730 -1,222 -5.32 1,218 1.42 0.0087
2017-08-10 2017-06-30 13F MARATHON PETE COM 56585A102 22,952 1,236 5.69 1,201 9.38 0.0096
2017-05-09 2017-03-31 13F MARATHON PETE COM 56585A102 21,716 -2,289 -9.54 1,098 -9.18 0.0100
2017-02-15 2016-12-31 13F MARATHON PETE COM 56585A102 24,005 2,150 9.84 1,209 36.30 0.0131
2016-11-14 2016-09-30 13F MARATHON PETE COM 56585A102 21,855 755 3.58 887 10.74 0.0136
2016-08-29 2016-06-30 13F MARATHON PETE COM 56585A102 21,100 -2,763 -11.58 801 -9.80 0.0115
2016-05-16 2016-03-31 13F MARATHON PETE COM 56585A102 23,863 10,634 80.38 888 29.45 0.0144
2016-02-16 2015-12-31 13F MARATHON PETE COM 56585A102 13,229 1,973 17.53 686 31.42 0.0137
2015-11-16 2015-09-30 13F MARATHON PETE COM 56585A102 11,256 -4,854 -30.13 522 -38.08 0.0124
2015-09-30 2015-06-30 13F/A-1 MARATHON PETE COM 56585A102 16,110 8,547 113.01 843 8.91 0.0219
2015-08-14 2015-06-30 13F MARATHON PETE COM 56585A102 17,638 1,141
2015-05-15 2015-03-31 13F MARATHON PETE COM 56585A102 7,563 2,150 39.72 774 58.28 0.0217
2015-02-13 2014-12-31 13F MARATHON PETE COM 56585A102 5,413 -332 -5.78 489 0.62 0.0151
2014-11-14 2014-09-30 13F MARATHON PETE COM 56585A102 5,745 533 10.23 486 19.41 0.0170
2014-08-05 2014-06-30 13F MARATHON PETE COM 56585A102 5,212 -529 -9.21 407 -18.60 0.0159
2014-05-15 2014-03-31 13F MARATHON PETE COM 56585A102 5,741 813 16.50 500 10.62 0.0209
2014-02-14 2013-12-31 13F MARATHON PETE COM 56585A102 4,928 152 3.18 452 47.23 0.0205
2013-11-14 2013-09-30 13F MARATHON PETE COM 56585A102 4,776 -44,779 -90.36 307 -91.28 0.0161
2013-08-21 2013-06-30 13F/A-1 MARATHON PETE COM 56585A102 49,555 49,555 3,521 0.2105
2013-08-14 2013-06-30 13F MARATHON PETE COM 56585A102 197,233 14,015 0.1541
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.