Marathon Petroleum Corporation
MX ˙ BMV ˙ US56585A1025
SecurityMX:MPC / Marathon Petroleum Corporation
InstitutionWelch & Forbes Llc
Latest Disclosed Ownership12,175 shares
Latest Disclosed Value $ 2,972,892
Welch & Forbes Llc ownership in MPC / Marathon Petroleum Corporation

On May 1, 2026 - Welch & Forbes Llc filed a 13F-HR form disclosing ownership of 12,175 shares of Marathon Petroleum Corporation (MX:MPC) valued at $2,972,892 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 10, 2026 disclosing 12,175 shares of Marathon Petroleum Corporation. This represents a change in shares of 0.00% 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)
2026-05-01 2026-03-31 13F MARATHON PETE COM 56585A102 12,175 0 0.00 2,973 50.10 0.0384
2026-02-10 2025-12-31 13F MARATHON PETE COM 56585A102 12,175 0 0.00 1,980 -15.60 0.0240
2025-11-04 2025-09-30 13F MARATHON PETE COM 56585A102 12,175 0 0.00 2,347 16.02 0.0283
2025-08-05 2025-06-30 13F MARATHON PETE COM 56585A102 12,175 0 0.00 2,022 14.04 0.0253
2025-05-02 2025-03-31 13F MARATHON PETE COM 56585A102 12,175 -103 -0.84 1,774 3.56 0.0232
2025-02-07 2024-12-31 13F MARATHON PETE COM 56585A102 12,278 430 3.63 1,713 -11.30 0.0220
2024-11-04 2024-09-30 13F MARATHON PETE COM 56585A102 11,848 88 0.75 1,930 0.78 0.0246
2024-08-02 2024-06-30 13F MARATHON PETE COM 56585A102 11,760 0 0.00 1,916 -19.16 0.0256
2024-05-03 2024-03-31 13F MARATHON PETE COM 56585A102 11,760 0 0.00 2,370 35.84 0.0325
2024-02-06 2023-12-31 13F MARATHON PETE COM 56585A102 11,760 0 0.00 1,745 -1.97 0.0264
2023-11-03 2023-09-30 13F MARATHON PETE COM 56585A102 11,760 -190 -1.59 1,780 27.71 0.0294
2023-07-28 2023-06-30 13F MARATHON PETE COM 56585A102 11,950 190 1.62 1,393 -12.11 0.0220
2023-04-14 2023-03-31 13F MARATHON PETE COM 56585A102 11,760 0 0.00 1,586 15.86 0.0269
2023-02-02 2022-12-31 13F MARATHON PETE COM 56585A102 11,760 0 0.00 1,369 17.12 0.0245
2022-10-31 2022-09-30 13F MARATHON PETE COM 56585A102 11,760 1,060 9.91 1,168 32.73 0.0228
2022-07-22 2022-06-30 13F MARATHON PETE COM 56585A102 10,700 0 0.00 880 -3.83 0.0161
2022-04-25 2022-03-31 13F MARATHON PETE COM 56585A102 10,700 0 0.00 915 33.58 0.0144
2022-01-19 2021-12-31 13F MARATHON PETE COM 56585A102 10,700 0 0.00 685 3.63 0.0103
2021-10-13 2021-09-30 13F MARATHON PETE COM 56585A102 10,700 -400 -3.60 661 -1.49 0.0110
2021-07-22 2021-06-30 13F MARATHON PETE COM 56585A102 11,100 0 0.00 671 12.96 0.0113
2021-04-14 2021-03-31 13F MARATHON PETE COM 56585A102 11,100 0 0.00 594 29.41 0.0110
2021-01-20 2020-12-31 13F MARATHON PETE COM 56585A102 11,100 0 0.00 459 40.80 0.0090
2020-10-23 2020-09-30 13F MARATHON PETE COM 56585A102 11,100 0 0.00 326 -21.45 0.0070
2020-07-15 2020-06-30 13F MARATHON PETE COM 56585A102 11,100 0 0.00 415 58.40 0.0097
2020-04-17 2020-03-31 13F MARATHON PETE COM 56585A102 11,100 -2,200 -16.54 262 -67.29 0.0073
2020-01-17 2019-12-31 13F MARATHON PETE COM 56585A102 13,300 0 0.00 801 -0.87 0.0178
2019-10-11 2019-09-30 13F MARATHON PETE COM 56585A102 13,300 0 0.00 808 8.75 0.0193
2019-07-12 2019-06-30 13F MARATHON PETE COM 56585A102 13,300 -2,937 -18.09 743 -23.56 0.0181
2019-04-29 2019-03-31 13F MARATHON PETE COM 56585A102 16,237 -988 -5.74 972 -4.33 0.0244
2019-02-05 2018-12-31 13F MARATHON PETE COM 56585A102 17,225 -537 -3.02 1,016 -28.45 0.0286
2018-10-17 2018-09-30 13F MARATHON PETE COM 56585A102 17,762 -200 -1.11 1,420 12.70 0.0338
2018-07-16 2018-06-30 13F MARATHON PETE COM 56585A102 17,962 -200 -1.10 1,260 -5.12 0.0326
2018-04-12 2018-03-31 13F MARATHON PETE COM 56585A102 18,162 -241 -1.31 1,328 9.39 0.0342
2018-01-26 2017-12-31 13F MARATHON PETE COM 56585A102 18,403 -134 -0.72 1,214 16.73 0.0324
2017-11-13 2017-09-30 13F MARATHON PETE COM 56585A102 18,537 -7,600 -29.08 1,040 -23.98 0.0274
2017-07-31 2017-06-30 13F MARATHON PETE COM 56585A102 26,137 -21 -0.08 1,368 3.48 0.0382
2017-07-31 2017-03-31 13F/A-1 MARATHON PETE COM 56585A102 26,158 21 0.08 1,322 0.46 0.0378
2017-04-27 2017-03-31 13F MARATHON PETE COM 56585A102 26,158 1,322
2017-02-07 2016-12-31 13F MARATHON PETE COM 56585A102 26,137 -537 -2.01 1,316 21.51 0.0394
2016-11-02 2016-09-30 13F MARATHON PETE COM 56585A102 26,674 0 0.00 1,083 6.91 0.0374
2016-08-02 2016-06-30 13F MARATHON PETE COM 56585A102 26,674 -1,000 -3.61 1,013 -1.55 0.0309
2016-05-05 2016-03-31 13F MARATHON PETE COM 56585A102 27,674 -500 -1.77 1,029 -29.57 0.0320
2016-01-27 2015-12-31 13F MARATHON PETE COM 56585A102 28,174 -200 -0.70 1,461 11.10 0.0469
2015-11-05 2015-09-30 13F MARATHON PETE COM 56585A102 28,374 0 0.00 1,315 -11.39 0.0439
2015-08-11 2015-06-30 13F MARATHON PETE COM 56585A102 28,374 14,187 100.00 1,484 2.13 0.0462
2015-04-30 2015-03-31 13F MARATHON PETE COM 56585A102 14,187 14,187 0.00 1,453 0.0437
2015-01-27 2014-12-31 13F MARATHON PETE COM 56585A102 0 -14,207 -100.00 0 -100.00
2014-10-27 2014-09-30 13F MARATHON PETE COM 56585A102 14,207 0 0.00 1,203 8.48 0.0367
2014-07-31 2014-06-30 13F MARATHON PETE COM 56585A102 14,207 300 2.16 1,109 -8.35 0.0350
2014-05-01 2014-03-31 13F MARATHON PETE COM 56585A102 13,907 0 0.00 1,210 -5.17 0.0383
2014-01-17 2013-12-31 13F MARATHON PETE COM 56585A102 13,907 0 0.00 1,276 42.73 0.0404
2013-10-31 2013-09-30 13F MARATHON PETE COM 56585A102 13,907 0 0.00 894 -9.51 0.0301
2013-08-08 2013-06-30 13F MARATHON PETE COM 56585A102 13,907 13,907 988 0.0353
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.